ArticlePDF Available

Maternal IgG immune complexes induce food allergen–specific tolerance in offspring

Authors:

Abstract and Figures

The role of maternal immune responses in tolerance induction is poorly understood. To study whether maternal allergen sensitization affects offspring susceptibility to food allergy, we epicutaneously sensitized female mice with ovalbumin (OVA) followed by epicutaneous sensitization and oral challenge of their offspring with OVA. Maternal OVA sensitization prevented food anaphylaxis, OVA-specific IgE production, and intestinal mast cell expansion in offspring. This protection was mediated by neonatal crystallizable fragment receptor (FcRn)–dependent transfer of maternal IgG and OVA immune complexes (IgG-IC) via breast milk and induction of allergen-specific regulatory T (T reg) cells in offspring. Breastfeeding by OVA-sensitized mothers or maternal supplementation with IgG-IC was sufficient to induce neonatal tolerance. FcRn-dependent antigen presentation by CD11c ⁺ dendritic cells (DCs) in offspring was required for oral tolerance. Human breast milk containing OVA-IgG-IC induced tolerance in humanized FcRn mice. Collectively, we demonstrate that interactions of maternal IgG-IC and offspring FcRn are critical for induction of T reg cell responses and control of food-specific tolerance in neonates.
This content is subject to copyright.
Article
The Rockefeller University Press
J. Exp. Med. 2018 Vol. 215 No. 1 91–113
https://doi.org/10.1084/jem.20171163
The Journal of Experimental Medicine
91
INTRODUCTION
Food allergy is a growing public health concern as it aects
5–8% of the U.S. population, has no eective cure, and can
be associated with life-threatening anaphylaxis (Sicherer and
Sampson, 2014). The disease is associated with CD4+ T cells
that secrete Th2 cytokines, and allergen-specic IgE anti-
bodies that activate mast cells (Metcalfe et al., 2009). Allergic
reactions to foods often occur on the rst known ingestion
(Sicherer et al., 1998), suggesting that exposure of ospring
to food allergens may occur in utero and/or through breast
milk. However, how maternal factors inuence food allergy
in ospring remains largely unknown. For example, eects of
maternal allergen exposure on development of allergies in o-
spring have been controversial. Past studies have identied an
increased risk (Sicherer et al., 2010) or no association (Lack et
al., 2003) of maternal peanut consumption with peanut sen-
sitization in ospring. In contrast, maternal exposure and/or
sensitization to food allergens could be benecial for protec-
tion of ospring from allergic diseases in humans and in mice
(Fusaro et al., 2007; López-Expósito et al., 2009; Mosconi et
al., 2010; Verhasselt, 2010b; Bunyavanich et al., 2014; Frazier
et al., 2014). Nevertheless, whether active tolerance is induced
in ospring has not been reported in these studies.
Forkhead box protein 3 (Foxp3)+ regulatory T (T reg)
cells regulate Th2 responses and food allergy in humans and
in mice (Chatila, 2005; van Wijk et al., 2007; Littman and
Rudensky, 2010; Ohkura et al., 2013; Noval Rivas et al.,
2015). However, whether maternal factors modulate T reg
cell–mediated tolerance in ospring remains elusive. Both
naturally occurring thymic-derived T reg cells and inducible
T reg cells derived from conventional CD4+ T cells in the
presence of TGF-β and specialized dendritic cells (DCs) such
as CD11c+CD103+ DCs suppress Th2 responses (Chatila,
2005; van Wijk et al., 2007; Curotto de Lafaille et al., 2008;
Gri et al., 2008; Akdis and Akdis, 2011). Successful immuno-
therapy is associated with increased T reg cells (Karlsson et
al., 2004; Shreer et al., 2009; Akdis and Akdis, 2011; Mou-
sallem and Burks, 2012) and allergen-specic IgG antibodies
(Scadding et al., 2010; Syed et al., 2014). Although protective
eects of allergen-specic IgG through competition with IgE
(Schroeder and Cavacini, 2010) and binding to inhibitory Fc
receptor FcγRIIB (Jarrett and Hall, 1979; Fusaro et al., 2002;
Utho et al., 2003; Till et al., 2004; Wachholz and Durham,
2004; Mosconi et al., 2010; Verhasselt, 2010a; Burton et al.,
2014a) in food allergy have been proposed, the role of IgG in
protective immune regulation requires further studies.
Neonatal crystallizable fragment receptor (FcRn) is ex-
pressed in intestinal epithelial cells until weaning in mice, and
throughout life in humans (Simister and Mostov, 1989; Dick-
inson et al., 1999). FcRn mediates the transfer of maternal
IgG to rodent ospring in early life, and thus plays a key role
The role of maternal immune responses in tolerance induction is poorly understood. To study whether maternal allergen sen-
sitization affects offspring susceptibility to food allergy, we epicutaneously sensitized female mice with ovalbumin (OVA)
followed by epicutaneous sensitization and oral challenge of their offspring with OVA. Maternal OVA sensitization prevented
food anaphylaxis, OVA-specic IgE production, and intestinal mast cell expansion in offspring. This protection was mediated
by neonatal crystallizable fragment receptor (FcRn)–dependent transfer of maternal IgG and OVA immune complexes (IgG-IC)
via breast milk and induction of allergen-specic regulatory T (T reg) cells in offspring. Breastfeeding by OVA-sensitized moth-
ers or maternal supplementation with IgG-IC was sufcient to induce neonatal tolerance. FcRn-dependent antigen presenta-
tion by CD11c+ dendritic cells (DCs) in offspring was required for oral tolerance. Human breast milk containing OVA-IgG-IC
induced tolerance in humanized FcRn mice. Collectively, we demonstrate that interactions of maternal IgG-IC and offspring
FcRn are critical for induction of T reg cell responses and control of food-specic tolerance in neonates.
Maternal IgG immune complexes induce food allergen–
specic tolerance in ospring
AsaOhsaki,1 NicholasVenturelli,1 TessM.Buccigrosso,2 StavroulaK.Osganian,2 JohnLee,1,5
RichardS.Blumberg,3,4,6* and MichikoK.Oyoshi1,5*
1Division of Immunology and 2Clinical Research Center, Boston Children’s Hospital, Boston, MA
3Gastroenterology Division, Brigham and Women’s Hospital, Boston, MA
4Department of Medicine and 5Department of Pediatrics, Harvard Medical School, Boston, MA
6Harvard Digestive Diseases Center, Boston, MA
© 2018 Ohsaki et al. This article is distributed under the terms of an Attribution–Noncommercial–Share
Alike–No Mirror Sites license for the rst six months after the publication date (see http ://www .rupress .org
/terms /). After six months it is available under a Creative Commons License (Attribution–Noncommercial–
Share Alike 4.0 International license, as described at https ://creativecommons .org /licenses /by -nc -sa /4 .0 /).
*R.S. Blumberg and M.K. Oyoshi contributed equally to this paper.
Correspondence to Michiko K. Oyoshi: michiko.oyoshi@childrens.harvard.edu
Maternal immune complexes form neonatal tolerance | Ohsaki et al.92
in neonatal passive immunity (Brambell, 1969; Simister and
Mostov, 1989; Leach et al., 1996; Simister et al., 1996). Recent
studies identied a much broader function of FcRn beyond
the neonatal period in humans and mice, including protec-
tion of IgG and albumin from catabolism (Chaudhury et al.,
2003; Roopenian et al., 2003; Pyzik et al., 2015), bidirectional
transport of IgG (but not IgA or IgM) between the lumen and
lamina propria (LP; Antohe et al., 2001; Claypool et al., 2002;
Spiekermann et al., 2002; Akilesh et al., 2008; Dickinson et al.,
2008; Bai et al., 2011; Li et al., 2011), and retrieval of antigen
as IgG and antigen immune complexes (IgG-IC) from lumen
to APCs such as DCs and macrophages in LP (Yoshida et al.,
2004, 2006). It has been proposed that after internalization
of IgG-IC into APCs by Fcγ receptors (FcγRs) on the cell
surface, FcRn binds to IgG-IC in acidic endosomes and con-
trols routing of IgG-IC to late endosomes, where antigen is
processed into peptide compatible with loading onto MHC
molecules, facilitating antigen presentation to T cells (Yoshida
et al., 2004, 2006; Qiao et al., 2008; Baker et al., 2011, 2013,
2014; Liu et al., 2011; Pyzik et al., 2015). Fc-fusion proteins
that bind to FcRn induce T reg cells and have been devel-
oped as therapeutic reagents (Lei and Scott, 2005; De Groot
et al., 2008; De Groot and Martin, 2009; Scott and De Groot,
2010; Rath et al., 2015). However, the role of FcRn in pro-
moting allergen-specic T reg cell response in early life is
currently underinvestigated.
Food allergy often coexists with atopic dermatitis (AD;
Eigenmann et al., 1998; Sicherer and Sampson, 1999; Hill et
al., 2007). AD is often the initial step in the so-called atopic
march, suggesting AD as a causal risk factor for subsequent
food allergy. Epidemiological data have shown that peanut
oil contaminants in baby lotions predispose to peanut allergy
(Lack et al., 2003) and that loss of function mutations in
the
Filaggrin
gene that encodes the epithelial barrier pro-
tein Filaggrin associated with AD also increase risk for food
allergy (Brown et al., 2011; Brough et al., 2014), implying
that increased allergen penetration through the damaged skin
barrier causes systemic allergen sensitization that may lead to
food allergy. Given the potential role of allergen sensitization
through the skin, we have previously established that epicuta-
neous allergen sensitization of mice through tape-stripped skin
over 7 wk results in food anaphylaxis (Bartnikas et al., 2013),
providing experimental support for this epidemiological hy-
pothesis linking skin allergen sensitization and food allergy.
Little is known about the role of maternally transferred
allergen and allergen-specic IgG in the development of al-
lergic diseases in ospring. To study the eects of maternal
allergen-specic immune responses on the susceptibility of
ospring to food allergy, we have further rened the epicuta-
neous sensitization model to develop an adjuvant-free, short
(9-d) protocol that retains key features of the previous model.
We hypothesized that maternal allergen sensitization induces
allergen-specic tolerance in ospring and protects against
food allergy. Female mice were epicutaneously sensitized
with allergen followed by epicutaneous sensitization and oral
challenge of their ospring with the same allergen. We have
demonstrated that maternal sensitization with allergen pro-
tected their ospring from the development of food-allergic
responses to the same allergen. This protection was mediated
by allergen-specic T reg cells in ospring. The interactions
of maternal IgG-IC in breast milk and ospring FcRn are es-
sential for the development of allergen-specic T reg cells. We
demonstrate that human breast milk containing OVA-IgG-IC
induced oral tolerance in humanized FcRn mice, substanti-
ating the importance of the IgG-IC-FcRn axis in neonatal
tolerance induction. Collectively, these data suggest that the
IgG-IC-FcRn axis may provide a therapeutic target to in-
duce tolerance in early life to prevent food allergy in children.
RESULTS
Maternal allergen sensitization protects
offspring against food allergy
To assess whether maternal allergen-specic immune re-
sponses inuence food allergic responses in ospring, we
epicutaneously sensitized 6–8-wk-old BALB/c WT female
mice with OVA or saline over 9 d before mating, and once
weekly during pregnancy and breastfeeding. 6–8-wk-old o-
spring were epicutaneously sensitized with OVA or saline fol-
lowed by oral OVA challenge by gavage at day 9 (Fig.1A).
Epicutaneous sensitization with OVA of ospring from sa-
line-exposed (unsensitized) mothers resulted in development
of food-allergic reactions as indicated by an increase in serum
OVA-specic IgE production. After oral OVA challenge,
mice exhibited serum levels of IL-4, systemic anaphylaxis in-
dicated by a drop in core body temperature, serum levels of
mouse mast cell protease-1 (mMCP1), frequencies and num-
bers of jejunal mast cells, and
Il13
mRNA expression in the
jejunum (Fig.1, B–I). Saline-exposed ospring from unsen-
sitized mothers showed no detectable changes in these pa-
rameters after oral OVA challenge (Fig.1, B–I). These results
are consistent with our previous ndings in mice epicutane-
ously sensitized over 7 wk (Bartnikas et al., 2013). In contrast
to OVA-sensitized ospring of unsensitized mothers, these
parameters of food-allergic responses were signicantly de-
creased in OVA-sensitized ospring of OVA-sensitized moth-
ers (Fig.1, B–I). To test whether the protection of ospring
from food allergy elicited by maternal allergen sensitization is
applicable to a clinically relevant food allergen, mothers were
sensitized with 0.45 mg commercial peanut butter (100 µg
protein) followed by epicutaneous sensitization (0.45 mg) and
oral challenge (225 mg) of their ospring with peanut but-
ter. Ospring of unsensitized mothers exhibited food-allergic
responses, including development of peanut-specic IgE,
systemic anaphylaxis, serum mMCP1, and jejunal mast cell
expansion. In contrast, these food-allergic responses were sig-
nicantly impaired in ospring of peanut-sensitized moth-
ers (Fig. S1). Collectively, these results suggest that maternal
allergen sensitization results in protection of ospring from
development of food-allergic response to epicutaneous sensi-
tization and oral challenge with the same allergens.
93JEM Vol. 215, No. 1
Figure 1. Maternal allergen sensitization protects offspring against food allergy. (A) Experimental protocol. (B) Serum OVA-IgE levels. (C) Serum IL-4
levels. (D) Core body temperature change 30 min after challenge. (E) Serum mMCP1 levels after challenge. (F) Representative ow cytometric analysis of
jejunal mast cells (c-kit+IgE+lineageCD45+) from two independent experiments. Numbers indicate percentages. (G–I) Mast cell frequencies (G), numbers (H),
and
Il13
mRNA (I) in the jejunum.
Il13
mRNA levels are expressed as fold induction relative to jejunum of saline (SAL)-exposed offspring of saline-exposed
mothers. Groups of animals were compared using nonparametric one-way ANO VA. Data are mean ± SEM of two independent experiments (B–E and G–I).
*, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, not signicant.
Maternal immune complexes form neonatal tolerance | Ohsaki et al.94
Maternal allergen sensitization induces allergen-specic
T reg cells in offspring
We next examined whether T reg cell responses are involved
in the protection of ospring against food allergy after mater-
nal allergen sensitization. Three-week-old weaned BALB/c
WT ospring of OVA-sensitized mothers exhibited an in-
crease in the frequencies and numbers of CD4+Foxp3+ T reg
cells in mesenteric lymph nodes (MLN) as compared with
weaned ospring of unsensitized mothers (Fig.2, A–C). To test
whether these T reg cells are allergen-specic, ospring MLN
cells were labeled with proliferation dye, stimulated in vitro
with OVA or peanut extract as an irrelevant allergen, and then
examined for expansion and proliferation as assessed by fre-
quencies of CD4+Foxp3+ cells and dye dilution, respectively.
In response to OVA stimulation, MLN cells from ospring of
OVA-sensitized mothers exhibited higher levels of expansion
(Fig.2D) and proliferation (Fig.2, E and F) of CD4+Foxp3+
T reg cells as compared with MLN cells from ospring of
unsensitized mothers. In contrast, MLN cells from ospring
of OVA-sensitized mothers did not show expansion or prolif-
eration of CD4+Foxp3+ T reg cells in response to stimulation
with peanut extract (Fig.2, D–F). There was no signicant
increase in expansion or proliferation of CD4+Foxp3+ T reg
cells in MLN cells from ospring of unsensitized mothers in
response to stimulation with OVA or peanut extract (Fig.2,
D–F). These results suggest that CD4+Foxp3+ T reg cells in
MLN of ospring from OVA-sensitized mothers expanded
and proliferated specically to OVA. We next tested the ca-
pacity of T reg cells from ospring of OVA-sensitized versus
ospring of unsensitized mothers to suppress OVA-specic
T cell proliferation in vitro. CD4+CD25+ T reg cells iso-
lated by magnetic beads from MLN of weaned BALB/c
WT ospring were cocultured with CD4+CD25DO11.10+
responder T cells labeled with proliferation dye in the pres-
ence of OVA323-339 peptide and irradiated WT splenocytes.
Proliferation of DO11.10+ T cells assessed by dye dilution
was signicantly less in the presence of T reg cells from o-
spring of OVA-sensitized mothers as compared with T reg
cells from ospring of unsensitized mothers (Fig. 2, G and
H), indicating that OVA-specic T reg cells from ospring
of OVA-sensitized mothers are capable of suppressing the
OVA-specic T cell response in vitro. After epicutaneous
sensitization with OVA of ospring, greater expansion of
OVA-specic CD4+Foxp3+ T reg cells was observed in MLN
of ospring from OVA-sensitized mothers as compared with
those in similarly sensitized ospring of unsensitized mothers
(Fig.2I). These results indicate that maternal allergen sensi-
tization elicits T reg cell responses in ospring that are spe-
cic to the same allergen.
Allergen-specic T reg cells in offspring are required for
protection against food allergy
To examine the possibility that allergen-specic T reg cells
in weaned ospring reduce disease susceptibility, we tested
whether inducible depletion of T reg cells in ospring of
OVA-sensitized mothers abolished the protection from food
allergy. We used a genetic approach in which lineage-specic
expression of the diphtheria toxin (DT) receptor (DTR) gene
in BALB/c
Foxp3EGFP/DTR+
mice allows selective Foxp3+ T
reg cell depletion by DT treatment (Haribhai et al., 2011).
4–6-wk-old
Foxp3EGFP/DTR+
ospring of OVA-sensitized
Foxp3EGFP/DTR+
mothers were treated with a single i.p. in-
jection of 50 µg/kg DT to eliminate T reg cells in ospring,
including OVA-specic T reg cells. Control
Foxp3EGFP/DTR+
littermates were injected with PBS. After DT treatment,
ospring were rested for 2 wk before OVA sensitization
for the recovery of Foxp3EGFP cells (Haribhai et al., 2011)
to avoid global T reg cell deciency (Fig.3A). In response
to epicutaneous sensitization and oral challenge with OVA,
DT-treated
Foxp3EGFP/DTR+
ospring of OVA-sensitized
mothers exhibited an increase in disease susceptibility, as in-
dicated by higher levels of OVA-IgE, systemic anaphylaxis,
serum mMCP1, and jejunal mast cell expansion as compared
with PBS-treated
Foxp3EGFP/DTR+
littermates (Fig. 3, B–F).
These results support the key role of allergen-specic T reg
cells induced by maternal allergen sensitization in induction
of tolerance in ospring.
Maternal IgG–allergen immune complexes, but not free
allergen, are transferred to weaned offspring via breast milk
Maternal allergen and Igs are transferred to ospring and
shape neonatal immune responses (Renz et al., 2011). Given
the development of allergen-specic T reg cells in weaned
ospring of allergen-sensitized mothers before direct expo-
sure of ospring to allergen, we hypothesized that allergens
are transferred from mothers to ospring before weaning and
induce allergen-specic T reg cells. BALB/c WT female mice
epicutaneously sensitized over 9 d with OVA, but not saline,
showed an increase in serum OVA-specic IgG1, OVA-IgG2a,
and OVA-IgE (Fig.4A), as previously reported (Nakajima et
al., 2012; Venturelli et al., 2016). Similarly, OVA-Igs were de-
tectable in breast milk and ospring sera of OVA-sensitized
mothers, but not of unsensitized mothers (Fig.4, B and C).
Unexpectedly, levels of free OVA in breast milk or ospring
sera of OVA-sensitized mothers were undetectable or close
to the lower detection limit (Fig.4, B and C). These results
led us to test whether allergen is transferred from moth-
ers to ospring as IgG-IC consisting of allergen and aller-
gen-specic Igs. Indeed, OVA-IgG1-IC and OVA-IgG2a-IC,
but not OVA-IgE-IC, were detectable in breast milk from
OVA-sensitized mothers but not in breast milk from unsensi-
tized mothers (Fig.4D and not depicted). Levels of TGF-β1
were also higher in breast milk from OVA-sensitized moth-
ers than in breast milk from unsensitized mothers (Fig.4D).
Consistently, ospring sera of OVA-sensitized mothers, but
not of unsensitized mothers, exhibited OVA-IgG1-IC and
OVA-IgG2a-IC (Fig.4E). OVA-IgA was virtually absent in
sera and breast milk from OVA-sensitized mothers, and sera
of ospring from OVA-sensitized mothers (not depicted).
These results suggest that allergens are transferred from aller-
95JEM Vol. 215, No. 1
Figure 2. Allergen-specic T reg cells expand in offspring of allergen-sensitized mothers. (A–C) Flow cytometric analysis (A), frequencies (B),
and numbers (C) of CD4+Foxp3+ cells in offspring MLN cells. (D) Analysis of OVA-specic Foxp3+ cells expanded from offspring MLN cells. (E and F) Flow
cytometric analysis (E) and frequencies (F) of proliferation among CD4+Foxp3+ MLN cells labeled with CellTrace Violet cultured in vitro for 5 d.
n
= 4 (D
and F). (G and H) Flow cytometric analysis (G) and percent suppression (H) of CellTrace Violet proliferation in DO11.10+ T responder cells cultured with
OVA323-339 peptide in the absence or presence of T reg cells isolated from offspring MLN cells. (I) Frequencies of OVA-specic Foxp3+ cells expanded from
offspring MLN cells after epicutaneous sensitization and oral challenge with OVA. Representative plots from two independent experiments are shown (A,
E, and G). Numbers indicate percentages (A and E). Groups of animals were compared using the Mann-Whitney
U
test (B, C, H, and I) or nonparametric
one-way ANO VA (D and F). Data are representative of two independent experiments (B–D, F, and H–I). Data are mean ± SEM. *, P < 0.05; **, P < 0.01;
ns, not signicant. SAL, saline.
Maternal immune complexes form neonatal tolerance | Ohsaki et al.96
gen-sensitized mothers as IgG-IC rather than as free allergen
to ospring via breast milk.
Breastfeeding by allergen-sensitized mothers protects
offspring from food allergy
Our data show that the protection of ospring by maternal
allergen sensitization is associated with the maternal IgG-IC
transfer via breast milk and the induction of allergen-specic
T reg cells in ospring. We hypothesized that maternal
IgG-IC transferred through breast milk as allergen is a key
factor in allergen-specic T reg cell induction in ospring. To
this purpose, BALB/c WT mothers exposed to saline (unsen-
sitized) or sensitized with OVA were coordinately mated, and
a part of ospring from unsensitized mothers were fostered
immediately after birth and nursed by OVA-sensitized moth-
ers until weaning. The remaining ospring from unsensitized
mothers were kept and nursed by unsensitized mothers. O-
spring of OVA-sensitized mothers were kept in the same cage
and nursed together with fostered ospring of unsensitized
mothers (Fig.5A). Breastfeeding by OVA-sensitized mothers
increased levels of serum OVA-IgG1-IC and OVA-IgG2a-IC
as well as OVA-specic T reg cells in MLN of fostered o-
spring at weaning similar to ospring of OVA-sensitized
mothers and higher than their littermates nursed by unsen-
sitized mothers (Fig. 5, B and C). In response to epicuta-
neous sensitization and oral challenge with OVA, fostered
Figure 3. Allergen-specic T reg cells in offspring are required for protection against food allergy. (A) Experimental protocol. (B) Serum OVA-IgE
levels. (C) Core body temperature change. (D) Serum mMCP1 levels. (E and F) Flow cytometric analysis of jejunal mast cell frequencies (E) and numbers (F).
Groups of animals were compared using the Mann-Whitney
U
test (B–F). Data are representative of two independent experiments (B–F). Data are mean ±
SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not signicant. SAL, saline.
97JEM Vol. 215, No. 1
ospring and ospring of OVA-sensitized mothers were
similarly protected from food-allergic responses, as levels of
serum OVA-IgE, systemic anaphylaxis, serum mMCP1, and
jejunal mast cell expansion were strongly impaired as com-
pared with OVA-sensitized ospring of unsensitized moth-
ers (Fig.5, D–H). These results indicate that breastfeeding by
allergen-sensitized mothers promotes allergen-specic T reg
cells and protection from food allergy in ospring. As mater-
nal Igs are also transferred through the placenta (Renz et al.,
2011), we have tested whether in utero–transferred IgG-IC
also participates in driving tolerance in ospring. To this pur-
pose, a part of ospring of OVA-sensitized mothers were
fostered immediately after birth and nursed by unsensitized
mothers (Fig. S2 A). Levels of maternal IgG-IC in fostered
ospring of OVA-sensitized mothers were higher than those
in ospring of unsensitized mothers and lower than in their
Figure 4. Maternal IgG-allergen im-
mune complex, but not free allergen, are
transferred to offspring via breast milk.
(A) OVA-specic Igs in mother sera. (B and C)
OVA-specic Igs and OVA in breast milk (B) and
offspring sera (C). (D) OVA-IgG-ICs and TGF-β1
in breast milk. (E) OVA-IgG-ICs in offspring
sera. Groups of animals were compared using
the Mann-Whitney
U
test. Data are mean ±
SEM of two independent experiments (A–E).
*, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P <
0.0001; ns, not signicant. SAL, saline.
Maternal immune complexes form neonatal tolerance | Ohsaki et al.98
littermates nursed by OVA-sensitized mothers (Fig. S2 B), in-
dicating transfer of maternal IgG-IC both in utero and via
breast milk. This was associated with a trend toward expan-
sion of OVA-specic T reg cells in MLN of weaned fostered
ospring that were signicantly lower than their littermates
nursed by OVA-sensitized mothers (Fig. S2 C). After epicu-
taneous sensitization and oral challenge with OVA, fostered
ospring of OVA-sensitized mice showed a decrease in serum
OVA-IgE levels and a trend toward lower systemic anaphy-
laxis, serum mMCP1, and jejunal mast cell expansion as com-
pared with OVA-sensitized ospring of unsensitized mothers
(Fig. S2, D–H), although these dierences did not reach statis-
tical signicance. These results suggest that maternal IgG-IC
transferred in utero to ospring may contribute to neonatal
tolerance and that IgG-IC transferred during breastfeeding is
necessary for optimal induction of tolerance in ospring of
OVA-sensitized mothers.
IgG-IC supplementation to mothers protects
offspring from food allergy
We next sought to directly test the role of IgG-IC in in-
duction of neonatal tolerance by supplementing naive
mothers with IgG-IC. We chose OVA-IgG1-IC based on
the higher concentrations of maternal OVA-IgG1-IC rel-
ative to OVA-IgG2a-IC in breast milk and ospring sera
from OVA-sensitized mothers (Fig. 4, D and E). In vitro–
formed OVA-IgG1-IC consisting mouse monoclonal anti-
OVA-IgG1 antibodies and OVA (Baker et al., 2013) was
given i.p. to naive BALB/c WT female mice once weekly for
6 wk during pregnancy and breastfeeding (Fig.6 A). Con-
trol BALB/c WT female mice were left untreated. Mater-
nal IC supplementation resulted in an increase in levels of
serum OVA-IgG1-IC and OVA-specic T reg cells in MLN
of ospring at weaning (Fig. 6, B and C). These were as-
sociated with protection of ospring from food-allergic re-
sponses after epicutaneous sensitization and oral challenge
with OVA, as indicated by a decrease in levels of serum
OVA-IgE, systemic anaphylaxis, serum mMCP1, and jeju-
nal mast cell expansion (Fig.6, D–H). As expected, ospring
of untreated mothers failed to show an increase in mater-
nal OVA-IgG1-IC, OVA-specic T reg cells, or protection
from food-allergic responses (Fig.6, B–H). To further dissect
the role of maternal IC during breastfeeding in induction of
tolerance in ospring, mothers were supplemented i.p. with
OVA-IgG1-IC once weekly for 3 wk only during breast-
feeding (Fig.6I). Ospring of mothers supplemented with
OVA-IgG1-IC during breastfeeding, but not ospring from
untreated mothers, exhibited an increase in levels of serum
OVA-IgG1-IC, OVA-specic T reg cells in MLN at weaning,
and protection from food-allergic responses after epicutane-
ous sensitization and oral challenge with OVA (Fig.6, J–P).
To test whether IgG-IC mediates neonatal tolerance directly
versus through the induction of allergen-specic T reg cells,
we examined food-allergic responses in ospring after ma-
ternal IgG and IgG-IC had been cleared from circulation.
Maternal OVA-Igs or OVA-IgG-ICs were undetectable in
15-wk-old BALB/c WT ospring (not depicted). 15-wk-old
ospring of OVA-sensitized mothers, but not of unsensitized
mothers, showed an expansion of OVA-specic T reg cells in
MLN (Fig. S3 A) and decreased food-allergic responses after
epicutaneous sensitization and oral challenge with OVA (Fig.
S3, B–F), suggesting that maternal allergen sensitization in-
duces long-lasting protection in ospring. Collectively, these
results demonstrate that maternal allergen IgG-IC plays a
critical role in establishing tolerance in ospring against food
allergy through induction of allergen-specic T reg cells.
Offspring FcRn is required for protection from food allergy
As FcRn is involved in the retrieval of IgG-IC from the
lumen into LP (Yoshida et al., 2004, 2006), we examined the
role of FcRn in induction of tolerance in ospring. BALB/c
Fcgrt+/
females were OVA-sensitized and mated with
BALB/c
Fcgrt
/
males (Fig. 7 A).
Fcgrt
/
females were
not used as they predictably exhibit a shorter IgG half-life
(Roopenian et al., 2003; Pyzik et al., 2015). Levels of serum
OVA-IgG1-IC and MLN OVA-specic T reg cells in weaned
Fcgrt+/
ospring were comparable to BALB/c WT ospring
of OVA-sensitized WT mothers, whereas there was no in-
crease in these parameters in
Fcgrt
/
littermates (Fig.7, B and
C). After epicutaneous sensitization and oral challenge with
OVA ,
Fcgrt+/
ospring of OVA-sensitized mothers exhib-
ited tolerance, as indicated by a decrease in levels of OVA-IgE
production, systemic anaphylaxis, and serum mMCP1,
and jejunal mast cell expansion (Fig. 7, D–H), whereas
OVA-sensitized
Fcgrt
/
ospring of OVA-sensitized moth-
ers failed to show tolerance against food-allergic responses
(Fig.7, D–H). Collectively, these results suggest that ospring
FcRn is essential in maternal IgG-IC transfer, dierentiation
of allergen-specic T reg cells, and induction of tolerance in
ospring, conrming the requirement of maternal IgG-IC
and ospring FcRn in disease protection.
Milk-borne allergen IgG-IC induces allergen-specic T reg
cells via MLN CD11c+ DCs
We hypothesized that maternal IgG-IC is processed and pre-
sented by CD11c+ DCs in ospring to promote the dier-
entiation of allergen-specic T reg cells. To test the capacity
of CD11c+ DCs to present milk-borne IgG-IC and to in-
duce allergen-specic T reg cells, CD11c+ DCs were isolated
from MLN of naive BALB/c WT mice and cocultured with
CD4+ T cells from
DO11.10+Foxp3EGFP Rag2
/
mice that
lack natural T reg cells in the presence or absence of breast
milk from saline- or OVA-sensitized mothers for 4 d. Breast
milk of OVA-sensitized mothers, but not breast milk of sa-
line-exposed mothers or PBS, increased the frequencies of
OVA-specic
Foxp3EGFP
T reg cells (Fig. 8, A and B), sug-
gesting that CD11c+ DCs process and present milk-borne
allergen IgG-IC and induce allergen-specic T reg cells. We
next compared the capacity of CD11c+ DCs from MLN of
ospring of saline- or OVA-sensitized mothers to induce
99JEM Vol. 215, No. 1
Maternal immune complexes form neonatal tolerance | Ohsaki et al.100
OVA-specic T reg cells in vitro without exogenous anti-
gen. CD11c+ DCs from ospring of OVA-sensitized mothers,
but not from saline-exposed mothers, induced OVA-specic
Foxp3EGFP
T reg cells (Fig. 8, C and D), indicating that
CD11c+ DCs from ospring of OVA-sensitized mothers al-
ready acquired allergen in vivo and induced allergen-specic
T reg cells. To examine the ability of CD11c+ DCs to induce
tolerance in vivo, MLN CD11c+ DCs were isolated from
BALB/c WT ospring of saline- or OVA-sensitized WT
mothers and adoptively transferred into naive BALB/c WT
recipients together with
DO11.10+Foxp3EGFP Rag2
/
CD4+
T cells (Fig. 8 E). After sensitization and oral challenge
with OVA, recipients of CD11c+ DCs from ospring of
OVA-sensitized mothers, but not of CD11c+ DCs from
ospring of saline-exposed mothers, exhibited a decrease
in food-allergic responses (Fig.8, F–J). Adoptive transfer of
CD11c+ DCs from ospring of OVA-sensitized mothers re-
sulted in greater expansion of OVA-specic T reg cells in vivo,
as assessed as
Foxp3EGFP
cells in MLN and jejunum (Fig.8, K
and L). These results indicate the critical role of CD11c+ DCs
in ospring in processing maternally transferred IgG-IC and
promoting T reg cell–mediated tolerance against food allergy.
FcRn in CD11c+ DCs is critical for induction
of tolerance in offspring
FcRn is expressed in DCs and macrophages throughout life
in humans and mice (Zhu et al., 2001). FcRn in APCs me-
diates antigen presentation of IgG-IC more eciently than
soluble antigen alone (Qiao et al., 2008; Baker et al., 2011).
Our results suggest that maternally transferred OVA-IgG-IC,
but not free OVA, processed and presented by CD11c+
DCs likely provides the basis for the development of aller-
gen-specic T reg cell responses in ospring. We hypothe-
sized that FcRn in ospring DCs contributes to tolerance
induction in ospring by facilitating IgG-IC presentation to
promote the induction of allergen-specic T reg cells during
this period of life. To this purpose, we examined the capacity
of CD11c+ DCs from MLN of naive BALB/c
Fcgrt
/ mice
to induce OVA-specic T reg cells in vitro in the presence
of breast milk from OVA-sensitized BALB/c WT mothers.
Unlike WT CD11c+ DCs,
Fcgrt
/ CD11c+ DCs failed to
induce OVA-specic T reg cells in response to breast milk
from OVA-sensitized mothers (Fig.9 A). WT and
Fcgrt
/
CD11c+ DCs were comparable in their capacity of inducing
OVA-specic T reg cells after in vitro stimulation with ex-
ogenous OVA323-339 peptide and TGF-β1 (Fig.9A), indicat-
ing that the impaired capacity of
Fcgrt
/ CD11c+ DCs in
inducing OVA-specic T reg cells was not a result of their
general failure to present allergens to CD4+ T cells. These re-
sults suggest that FcRn in CD11c+ DCs is required for ma-
ternal allergen presentation and induction of antigen-specic
T reg cells. To further examine the role of FcRn in CD11c+
DCs in induction of tolerance in vivo, we used mice bear-
ing a oxed
Fcgrt
gene (
Fcgrt/
) crossed with CD11c-cre
mice on C57BL/6 background to specically delete FcRn
in CD11c+ DCs (C57BL/6
Itgaxcre Fcgrt/
). Saline- or
OVA-sensitized
Fcgrt/
females were mated with
Itgaxcre
Fcgrt/
males (Fig. 9B). Weaned
Itgaxcre Fcgrt/
ospring
of OVA-sensitized mothers exhibited a decrease in induc-
tion of OVA-specic T reg cells as compared with
Fcgrt/
littermates (Fig. 9 C). Consistently,
Itgaxcre Fcgrt/
ospring
of OVA-sensitized mothers failed to exhibit tolerance to food
allergy, as
Itgaxcre Fcgrt/
mice developed greater levels of
OVA-IgE, systemic anaphylaxis, and jejunal mast cell expan-
sion than their
Fcgrt/
littermates in response to epicutane-
ous sensitization and oral challenge with OVA (Fig.9, D–G).
IgG-IC in human breast milk protects humanized
FcRn mice from food allergy
Food-specic IgG and food allergen–immune complexes are
present in sera and breast milk of healthy subjects (Husby et
al., 1985; Rumbo et al., 1998; Hirose et al., 2001; Bernard
et al., 2014; Hochwallner et al., 2014; Schwarz et al., 2016).
Elevated levels of allergen-specic IgG, especially IgG4, are
associated with successful allergen-specic immunotherapy
(Skripak et al., 2008; Caubet et al., 2012; James et al., 2012).
The presence of OVA-specic IgG4 and OVA-IgG4-IC was
assessed in breast milk samples from 16 nonatopic mothers
by ELI SA. OVA-IgG4 was detectable in 10 (62.5%) milk
samples with a median value among positive samples of 95.8
ng/ml (Table S1). OVA-IgG4-IC was present in 8 subjects
among 10 subjects that were positive for OVA-IgG4 (Table
S1). OVA-IgE was undetectable in all samples. These results
together with the ndings in our mouse models suggest that
maternal food-specic IgG in breast milk may promote the
development of neonatal tolerance if transferred to neo-
nates together with food allergen. To examine the capacity
of IgG-IC from human breast milk to promote induction of
neonatal tolerance and to demonstrate a direct link between
human FcRn and neonatal tolerance induction, we used
BALB/c mice that constitutively express human FcRn and
β2-microglobulin (β2M) and are decient in mouse FcRn
(
hFCG RT-hB2M-mFcgrt
/
) and thus have only the human
form of the receptor (Roopenian et al., 2003; Yoshida et al.,
2004). BALB/c
hFCG RT-hB2M-mFcgrt
/
mice were sup-
plemented by gavage 2 times a week for 2 wk with pooled
Figure 5. Breastfeeding by allergen-sensitized mothers protects offspring from food allergy. (A) Experimental protocol. (B) Serum OVA-IgG-ICs
in weaned offspring. (C) Analysis of OVA-specic Foxp3+ cells expanded from offspring MLN cells. (D) Serum OVA-IgE levels. (E) Core body temperature
change. (F) Serum mMCP1 levels. (G and H) Flow cytometric analysis of jejunal mast cell frequencies (G) and numbers (H). Groups of animals were com-
pared using nonparametric one-way ANO VA. Data are mean ± SEM of two independent experiments (B–H). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not
signicant. SAL, saline.
101JEM Vol. 215, No. 1
Maternal immune complexes form neonatal tolerance | Ohsaki et al.102
human breast milk samples positive for OVA-IgG4-IC fol-
lowed by epicutaneous sensitization and oral challenge with
egg white protein (Fig.10A). Treatment of humanized FcRn
mice with OVA-IgG4-IC–containing breast milk resulted in
oral tolerance, as indicated by an increase in allergen-specic
T reg cells and a decrease in allergen-specic IgE, oral ana-
phylaxis, and jejunal mast cells (Fig.10, B–F). The hypothesis
that OVA-IgG4-IC mediated the observed protection in hu-
manized FcRn mice from food allergy was tested by treat-
ment of humanized FcRn mice with the same milk after IgG
depletion. Removal of IgG from OVA-IgG4-IC–containing
milk abrogated the dierentiation of allergen-specic T reg
cells as well as suppressive eects of milk on food-allergic re-
sponses (Fig.10, B–F). Collectively, these results indicate that
allergen-specic IgG-IC in breast milk drive allergen-specic
T reg cells and that food-specic IgG antibodies exert an
induction of tolerance against food allergy. These data further
support the concept that the IgG-IC-FcRn axis contributes
to neonatal tolerance induction and may extend to humans.
DISCUSSION
In this study, we demonstrate that the interactions of maternal
food allergen–specic IgG-IC and ospring FcRn in induc-
tion of allergen-specic T reg cell responses are fundamental
to establishment of an eective, long-lasting neonatal toler-
ance to foods. Food allergen–specic IgG-IC is also observed
in human breast milk from nonatopic mothers and sucient
to reduce disease susceptibility in humanized FcRn mice.
By using a physiological mouse model that shares fea-
tures of human food allergy, including a portal of exposure
(the skin) that is important for disease development, and re-
sponse to oral challenge with IgE- and mast cell–mediated
anaphylaxis, we demonstrated that maternal sensitization with
food allergen induces T reg cells in ospring that are specic
to the same allergen, which mediate the protection from food
allergy. Allergen-specic T reg cells were induced by mater-
nal IgG-IC in breast milk, which was transferred to ospring
in an FcRn-dependent manner, followed by FcRn-mediated
antigen presentation by CD11c+ DCs in ospring. These
ndings outline a cascade of cellular and molecular events
that underlie the induction of neonatal tolerance toward food
allergens elicited by maternal immune responses.
BALB/c WT ospring of unsensitized mothers devel-
oped food-allergic responses after epicutaneous sensitization
over 9 d and oral challenge with OVA, with increased levels
of serum OVA-IgE, systemic anaphylaxis, serum mMCP1,
and jejunal mast cell expansion. Our adjuvant-free model
eliminates in mothers and ospring potentially confounding
eects of adjuvants such as alum and cholera toxin (Oyoshi et
al., 2014) that were used in previous studies examining ma-
ternal eects on ospring allergies (Leme et al., 2006; Matson
et al., 2009; Mosconi et al., 2010). It is also highly versatile
as it is operative in dierent backgrounds including BALB/c
and C57BL/6. We demonstrate that maternal allergen sensi-
tization results in protection of ospring from development
of food allergy, as the disease features were strongly attenu-
ated in ospring of OVA-sensitized mothers. This protection
was long-lasting, as food-allergic responses were suppressed in
15-wk-old ospring from OVA-sensitized mothers.
This protection of ospring against food allergy was
associated with an increase in allergen-specic Foxp3+ T reg
cells in ospring at weaning, as indicated by the capacities
of these T reg cells to expand, proliferate, and suppress T
cell proliferation in an allergen-specic manner. Although
natural or type 1 T reg cells could also suppress food al-
lergy, the critical importance of allergen-specic T reg cells
in ospring in mediating neonatal tolerance was evident in
in vivo models, as depletion of allergen-specic T reg cells
in
Foxp3EGFP/DTR+
ospring of allergen-sensitized mothers
abolished tolerance against food allergy.
The dierentiation of allergen-specic T reg cells in
ospring at weaning reected the role of maternally trans-
ferred IgG-IC via breast milk. Maternal OVA-Igs were in-
creased in sera and breast milk from OVA-sensitized mothers,
which were also observed in ospring sera of OVA-sensitized
mothers. Although maternal OVA-IgE was detectable in o-
spring of OVA-sensitized mothers, oral OVA challenge of
saline-exposed ospring of OVA-sensitized mothers did not
result in systemic anaphylaxis, consistent with the observations
in humans and in mice that the presence of allergen-specic
IgE is not always associated with food allergy symptoms (Bart-
nikas et al., 2013; Valenta et al., 2015). Although mothers were
constantly exposed to OVA from preconception through
weaning, levels of free OVA in breast milk or sera of ospring
from OVA-sensitized mothers were negligible, whereas sim-
ilar ELI SA protocols readily detected IgG-IC and OVA-Igs
not bound to OVA in the same samples. Although it is possi-
ble that undetectable levels of OVA in breast milk could also
be transferred to ospring, these results suggest that transfer of
free antigen to the pups during breastfeeding period is likely
minimal. Our results suggest that in utero–transferred IgG-IC
may also participate in driving tolerance in ospring and that
Figure 6. IC supplementation to mothers protects offspring from food allergy. (A–H) IC supplementation during pregnancy and breastfeeding.
Experimental protocol (A), serum OVA-IgG1-IC in weaned offspring (B), OVA-specic Foxp3+ cells expanded from offspring MLN cells (C), serum OVA-IgE
levels (D), core body temperature change (E), serum mMCP1 levels (F), jejunal mast cell frequencies (G), and numbers (H). (I–P) IC supplementation during
breastfeeding. Experimental protocol (I), serum OVA-IgG1-IC in weaned offspring (J), OVA-specic Foxp3+ cells expanded from offspring MLN cells (K),
serum OVA-IgE levels (L), core body temperature change (M), serum mMCP1 levels (N), jejunal mast cell frequencies (O), and numbers (P). Groups of animals
were compared using the Mann-Whitney
U
test. Data are mean ± SEM and representative of 2 independent experiments (B–H, J–P). *, P < 0.05; **, P < 0.01;
***, P < 0.001; ****, P < 0.0001.
103JEM Vol. 215, No. 1
Figure 7. Offspring FcRn is required for protection of offspring from food allergy. (A) Experimental protocol. (B) Serum OVA-IgG1-IC in weaned off-
spring. (C) Analysis of OVA-specic Foxp3+ cells expanded from offspring MLN cells. (D) Serum OVA-IgE levels. (E) Core body temperature change. (F) Serum
mMCP1 levels. (G and H) Flow cytometric analysis of jejunal mast cell frequencies (G) and numbers (H). Groups of animals were compared using nonpara-
metric one-way ANO VA. Data are mean ± SEM of two independent experiments (B–H). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not signicant. SAL, saline.
Maternal immune complexes form neonatal tolerance | Ohsaki et al.104
Figure 8. Milk-borne IgG-IC induces allergen-specic T reg cells via MLN CD11c+ DCs. (A and B) Flow cytometric analysis (A) and frequencies (B)
of CD4+DO11.10+Foxp3EGFP+ T reg cells. MLN CD11c+ cells were isolated from naive WT mice and cultured with CD4+DO11.10+Foxp3EGFP- cells in the presence
or absence of breast milk. (C and D) Flow cytometric analysis (C) and frequencies (D) of CD4+DO11.10+Foxp3EGFP+ T reg cells. MLN CD11c+ cells were isolated
105JEM Vol. 215, No. 1
IgG-IC transferred during breastfeeding is necessary for op-
timal induction of tolerance. This was further supported by
the ndings that breastfeeding by OVA-sensitized mothers
was sucient to increase IgG-IC levels and allergen-specic
T reg cells, as well as protection against food allergy in fos-
tered ospring of unsensitized mothers, similar to ospring of
OVA-sensitized mothers.
The direct contribution of maternal IgG-IC to toler-
ance induction was evident as maternal IC supplementation
during pregnancy and breastfeeding promoted neonatal toler-
ance against food allergy. Maternal IgG-IC supplementation
only during breastfeeding resulted in lower levels of IgG-IC
in ospring as compared with maternal IgG-IC supplemen-
tation during pregnancy and breastfeeding, likely reecting
the total IgG-IC dose given to mothers and the contribu-
tion of in utero IgG-IC transfer. Although physiological dose
requirements for IgG-IC to induce neonatal tolerance are
unknown, maternal IgG-IC supplementation during breast-
feeding alone still provided resistance toward food allergy in
ospring. This further supports the critical role of IgG-IC in
induction of neonatal tolerance. The essential role of ospring
FcRn in tolerance induction was shown in an in vivo model.
BALB/c
Fcgrt+/
ospring of OVA-sensitized
Fcgrt+/
mothers showed comparable levels of maternal IgG-IC
transfer, allergen-specic T reg cell induction, and protection
against food allergy as in WT controls. Impaired formation of
allergen-specic T reg cells and failure of tolerance induction
in BALB/c
Fcgrt
/
littermates of OVA-sensitized
Fcgrt+/
mothers were associated with their inability to receive and
respond to maternal IgG-IC, consistent with a previous study
that ospring FcRn is required for maternal IgG-IC trans-
fer and protection against experimental asthma (Mosconi et
al., 2010). A previous study evaluated mothers and ospring
immunized through a nonphysiological route (i.p.) with an
articial adjuvant, alum, which induces allergic airway in-
ammation that is independent of IgE or mast cells (Wil-
liams and Galli, 2000). In this study, mothers were exposed to
OVA aerosols after adoption of ospring, raising a possibility
that mothers and ospring ingested OVA by licking their fur.
Thus, their results of neonatal tolerance induction may have
reected exposure of mothers and ospring to OVA by both
airway and oral routes. The capacity of IgG-IC to induce T
reg cell–mediated tolerance and the role of FcRn in DCs
were not directly addressed in the previous study. Further-
more, the mechanisms suggested using a mouse model of al-
lergic airway inammation do not necessarily extend to the
mechanisms applicable to a model of food allergy. Our model
is likely to be more relevant to naturally occurring sensiti-
zation to food allergens in that it is adjuvant-free, uses skin
as a route of exposure that is important for development of
clinical food allergy, is applicable to a clinically relevant pea-
nut allergen, and assesses responses to oral challenge together
with IgE- and mast cell–mediated anaphylaxis (Bartnikas et
al., 2013; Galand et al., 2016).
The mechanism driving the dierentiation of aller-
gen-specic T reg cells involved maternal antigen presenta-
tion by CD11c+ DCs in ospring. CD11c+ DCs from MLN
of naive BALB/c WT mice supported induction of aller-
gen-specic T reg cells in the presence of breast milk from
OVA-sensitized mothers in vitro. In addition, CD11c+ DCs
from ospring of OVA-sensitized mothers induced aller-
gen-specic T reg cells in vitro without addition of exoge-
nous antigen, indicating that these cells acquired maternally
transferred antigens in vivo, likely as IgG-IC, given the ab-
sence of free OVA in breast milk from OVA-sensitized moth-
ers. We further demonstrated that CD11c+ DCs from MLN
in ospring promote dierentiation of allergen-specic T
reg cells that mediate tolerance in vivo. Adoptive transfer of
CD11c+ DCs from ospring of OVA-sensitized mothers, but
not CD11c+ DCs from ospring of unsensitized mothers,
transferred tolerance in recipients.
In addition to mediating maternal IgG-IC transfer to
ospring through intestinal epithelial cells as supported by
our previous studies (Yoshida et al., 2004), FcRn in CD11c+
DCs in ospring was also critical for maternal IgG-IC pro-
cessing and antigen presentation to induce allergen-specic
T reg cells. Unlike WT CD11c+ DCs,
Fcgrt
/ CD11c+ DCs
were incapable of presenting OVA-IgG-IC in breast milk
from OVA-sensitized mothers to induce allergen-specic T
reg cells in vitro. These results are consistent with the dis-
tinctive role of FcRn in CD11c+ DCs in processing IgG-IC,
rather than soluble antigen, to prime T cell responses (Qiao et
al., 2008; Baker et al., 2011) and further support our concept
that IgG-IC in breast milk provides the main basis of aller-
gen-specic T reg cell dierentiation. The requisite role of
FcRn in CD11c+ DCs in determining the tolerogenic envi-
ronment was further demonstrated by us in vivo in mice with
CD11c+ cell–specic FcRn deciency, which failed to in-
crease allergen-specic T reg cells and tolerance induction by
maternal allergen sensitization. Previous studies have linked
FcRn-dependent antigen processing to the induction of Th1
responses via induction of IL-12 production by CD11c+ cells
(Baker et al., 2013). Our studies here thus extend these ob-
servations by showing that FcRn in CD11c+ cells in response
from offspring of SAL or OVA mothers and cultured with CD4+DO11.10+Foxp3EGFP- cells without exogenous allergens. (E–L) Adoptive transfer of MLN CD11c+
cells from offspring of SAL or OVA mothers. Experimental protocol (E), OVA-IgE (F), core body temperature change (G), serum mMCP1 levels (H), jejunal
mast cell frequencies (I) and numbers (J), and ow cytometric analysis of CD4+DO11.10+Foxp3EGFP+ T reg cells in MLN (K) and jejunum (L) of recipients.
Representative plots from two independent experiments shown (A and C). Numbers indicate percentages (A and C). Groups of animals were compared
using nonparametric one-way ANO VA (B) and the Mann-Whitney
U
test (D and F–L). Data are mean ± SEM of two independent experiments (B and D) or
representative of two independent experiments (F–L). *, P < 0.05; **, P < 0.01; ns, not signicant. SAL, saline.
Maternal immune complexes form neonatal tolerance | Ohsaki et al.106
Figure 9. FcRn in CD11c+ DCs is critical for induction of tolerance in offspring. (A) Flow cytometric analysis of CD4+DO11.10+Foxp3EGFP+ T reg cells.
MLN CD11c+ DCs were isolated from WT or
Fcgrt
/
mice and cultured with CD4+DO11.10+Foxp3EGFP- cells with breast milk from OVA-sensitized WT mothers
or with exogenous TGF-β1 and OVA323-339 peptide. (B) Experimental protocol. (C) Analysis of OVA-specic Foxp3+ cells expanded from weaned offspring MLN
cells. (D) Serum OVA-IgE levels. (E) Core body temperature change. (F and G) Flow cytometric analysis of jejunal mast cell frequencies (F) and numbers (G).
Groups of animals were compared using the Mann-Whitney
U
test (A, C–G). Data are mean ± SEM of two independent experiments (A) or 3 independent
experiments (C–G). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ns, not signicant. SAL, saline.
107JEM Vol. 215, No. 1
to IgG-IC also regulates the induction of FoxP3+ T reg cells.
Whether this is a result of the activities of FcRn in specic
subsets of APCs and in a tissue- and/or age-dependent man-
ner remains to be addressed. Our study delineates for the rst
time the critical role of FcRn in DCs in promoting aller-
gen-specic T reg cell responses, which together provides
a greater understanding of the role of FcRn in modulating
protective immune regulation in food allergy. Our results thus
provide a novel role of FcRn in mediating allergen-specic T
reg cell responses in mediating neonatal tolerance, on the top
of its known role in the maternal IgG transfer.
FcRn may thus control tolerance induction at many
points of life. These include the role played by FcRn in con-
trolling the transport of IgG-IC across the placenta ante-
natally into the developing fetus (Leach et al., 1996). FcRn
function in intestinal epithelial cells of the neonatal animal
may be particularly important in the rodent during neonatal
life when FcRn expression and function are robust (Gill et al.,
1999). Although never directly addressed, FcRn in intestinal
epithelial cells may play a role in the antigen presentation
functions of this cell type in the induction of tolerance (Kai-
serlian et al., 1989). These possibilities are of potential future
interest through conditional deletion of
Fcgrt
in the intestinal
epithelium, for example.
As IgG-IC processing also requires FcγR (Baker et
al., 2011), the contribution of each FcγR to IgG-IC up-
take by CD11c+ DCs leading to the T reg cell induction is
not clear and an important future area of study. One recent
study demonstrated a critical role for FcγRIIb in mediating a
protective eect of allergen-specic IgG against food allergy
(Burton et al., 2017). Nevertheless, it may be hypothesized
that after the internalization of IgG-IC by FcγRs, FcRn is
the only intracellular receptor that is known to control the
routing of IgG-IC to an antigen-processing pathway to prime
Figure 10. IgG-IC in human breast milk protects humanized FcRn mice from food allergy. (A) Experimental protocol. (B) Analysis of allergen-specic
Foxp3+ cells expanded from MLN cells. (C) Serum egg white-IgE levels. (D) Core body temperature change. (E and F) Flow cytometric analysis of jejunal mast
cell frequencies (E) and numbers (F). Groups of animals were compared using a nonparametric one-way ANO VA. Data are mean ± SEM and representative
of two independent experiments (B–F). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not signicant.
Maternal immune complexes form neonatal tolerance | Ohsaki et al.108
T cells (Qiao et al., 2008; Baker et al., 2011, 2013, 2014; Liu
et al., 2011; Guilliams et al., 2014).
We demonstrate in the current study that food-specic
IgG4 is detectable in breast milk from nonatopic mothers,
consistent with the previous studies (Bernard et al., 2014;
Rekima et al., 2017). Furthermore, OVA-IgG4-IC was com-
monly present in breast milk samples that were positive for
OVA-IgG4. The importance of the milk-borne IgG-IC-FcRn
axis in tolerance induction was strongly corroborated by the
impaired food-allergic responses in humanized FcRn mice
supplemented with breast milk from nonatopic mothers con-
taining OVA-IgG-IC, but not with IgG-depleted milk. These
results further validate that the concept of inducing oral tol-
erance by the IgG-IC pathway is also eective when human
breast milk IgG-IC is used, providing a particularly important
piece of evidence for the potential clinical relevance of our
observations in mice for humans.
Our study is in line with recent ndings that mater-
nal exposure to food allergens decreases allergy in ospring
in humans and in mice (Fusaro et al., 2007; López-Expósito
et al., 2009; Mosconi et al., 2010; Verhasselt, 2010b; Bunya-
vanich et al., 2014; Frazier et al., 2014). Prior human studies
examining the eect of maternal diets during pregnancy on
peanut allergy have shown inconsistent results. A prospective
US study showed no benet of maternal and early childhood
avoidance of milk, egg, or peanut in preventing food allergies
(Zeiger et al., 1989). Our results provide experimental sup-
port for recent decisions to withdraw recommendations of
allergen avoidance during pregnancy and breastfeeding, and
support potential benecial eects of maternal allergen ex-
posure to protect ospring from food allergy. A recent study
suggesting that early food introduction might decrease the
risk of food allergy development (Perkin et al., 2016) under-
scored the potential benet of food allergen transfer through
breast milk as this may be the rst food exposure for the in-
fant. Our data indicate that both ospring of sensitized moth-
ers and ospring of unsensitized mothers supplemented with
IgG-IC exhibited tolerance against food allergy, highlighting
the critical role of maternal IgG-IC in tolerance induction
in ospring regardless of the sensitization status of mothers
in our mouse model. Our ndings that food allergen–spe-
cic IgG-IC is present in human breast milk from nonatopic
mothers and sucient to reduce disease susceptibility in hu-
manized FcRn mice support that nonatopic mothers may
induce oral tolerance through the IgG-IC pathway. Analysis
of how the atopic status of mothers may inuence tolerance
induction in ospring in humans will be an important future
question to be addressed.
In summary, this study has provided novel exper-
imental evidence supporting a critical role of maternal al-
lergen-specic immune responses in establishing eective
tolerance that prevents food allergy in ospring, extending
well beyond the previously known roles of maternal anti-
bodies and FcRn in providing passive immunity. Our exper-
imental approaches that combine cellular and in vivo animal
investigations as well as human ex vivo samples demonstrate
that the interactions of IgG-IC and FcRn are critical in the
development of neonatal tolerance, namely FcRn-dependent
transfer of maternal IgG-IC and FcRn-dependent IgG-IC
processing and antigen presentation by CD11c+ DCs to in-
duce allergen-specic T reg cells in ospring (Fig. S4), thus
identifying multiple roles for FcRn in neonatal tolerance.
Our results also provide a rationale for measures that improve
the development of allergen-specic T reg cells through ma-
ternal allergen exposure. This previously unrecognized tol-
erance pathway could suggest a potential for IgG-IC as an
immunotherapy to improve oral tolerance and may lead to
improved therapeutic strategies to induce tolerance in early
life to prevent food allergy in children.
MATERIALS AND METHODS
Study participants
Nonatopic breastfeeding mothers were recruited as dened by
no personal or family history of atopic diseases (food allergy,
environmental allergy, eczema, asthma) in rst-degree rela-
tives. These subjects had no other chronic diseases or mastitis
during the preceding 4 wk. Informed consent was obtained
from the subjects and the study was approved by the Boston
Children’s Hospital Institutional Review Board. Milk samples
were centrifuged (400
g
, 15 min), fat was removed, and su-
pernatant was collected, frozen, and stored at 20°C until use.
Mice
BALB/c WT mice were purchased from Taconic. BALB/c
Foxp3EGFP/DTR+
and BALB/c
DO11.10+Rag2
/
Foxp3EGFP
mice bred onto a BALB/c background for >10 genera-
tions were a gift from T. Chatila (Boston Children’s Hospital,
Boston, MA).
Fcgrt
/ (Roopenian et al., 2003) and
hFCG
RT-hB2M-mFcgrt
/
(Roopenian et al., 2003; Yoshida et al.,
2004) mice were bred onto a BALB/c background for more
than 10 generations. C57BL/6
Fcgrt/
mice were kindly
provided by E.S. Ward (University of Texas Southwestern
Medical Center, Dallas, TX; Yoshida et al., 2004; Montoyo et
al., 2009). All mice were bred in the animal facility of Bos-
ton Children’s Hospital, kept in a specic pathogen-free en-
vironment, and fed an OVA-free diet. All procedures were
performed in accordance with the Animal Care and Use
Committee of Boston Children’s Hospital.
Allergen sensitization and anaphylaxis
Epicutaneous sensitization of mice was performed as previ-
ously described (Venturelli et al., 2016). In brief, the dorsal
skin of anesthetized 6–8-wk-old female mice was shaved and
tape-stripped six times with Tegaderm (Westnet Inc.). Then
100 µg OVA (Grade V; Sigma) in 100 µl of nor mal saline,
or placebo (100µl of nor mal saline), was placed on a patch
of sterile gauze (1 × 1 cm), which was secured to the dorsal
skin with Tegaderm. Each mouse had a total of three 1-d ex-
posures to the patch separated by 2-d intervals over 9 d be-
fore mating. Female mice received epicutaneous sensitization
109JEM Vol. 215, No. 1
with OVA once weekly during pregnancy and breastfeeding.
Mothers did not receive oral OVA challenge. 6–8-wk-old
ospring were epicutaneously sensitized with OVA or saline
over 9 d followed by a bolus oral challenge with 100 mg OVA
at day 9 (Bartnikas et al., 2013). Temperature changes were
measured by using the DAS-6006 Smart Probe and transpon-
ders (Biomedic Data Systems) injected subcutaneously. Mice
were euthanized 24h after challenge to harvest tissues. For T
reg cell depletion by DT,
Foxp3EGF PDTR+
mice were treated
i.p. with 50 µg/kg DT (List Biological Laboratory).
Fostering of offspring
Mothers sensitized with saline or OVA were coordinately
mated, and ospring of saline- or OVA-exposed mothers
were fostered and nursed by OVA- or saline-sensitized moth-
ers. Ospring of OVA- or saline-sensitized mothers were
kept in the original cage and nursed by OVA- or saline-sen-
sitized mothers together with fostered ospring of saline-
or OVA-exposed mothers.
Breast milk collection
Mouse breast milk was collected after i.p. injection of
4 IU oxytocin (Sigma) 24 h after OVA sensitization
of breastfeeding mothers.
IC supplementation
OVA-IgG1-IC was formed as previously described (Baker et
al., 2011). In brief, mouse monoclonal anti-OVA-IgG1 anti-
bodies puried using A-Gel Protein A MAPS II kit (Biorad)
from hybridoma (clone 01–4), a kind gift of H. Karasuyama
(Tokyo Medical and Dental University, Tokyo, Japan), was
incubated at 1:2 molar ratio of anti-OVA-IgG1 to OVA at
37°C for 30 min. OVA-IgG1-IC (100 µg) was given i.p. to
BALB/c WT female mice once weekly for 6 wk during preg-
nancy and breastfeeding, or for 3 wk during breastfeeding.
Human breast milk supplementation
3–5-wk-old
hFCG RT-hB2M-mFcgrt
/
mice were treated
by gavage twice a week for 2 wk with 300µl pooled human
breast milk samples containing OVA-IgG4-IC, the same
breast milk samples depleted of IgG, or PBS. IgG depletion
was performed with the Nab Protein G Spin kit (Thermo
Scientic) according to the manufacturer’s instructions. Mice
were epicutaneously sensitized with 200 µg egg white ex-
tract (Greer) and orally challenged with 200 mg egg white
protein (Nutriom LLC) as described above (Allergen sensiti-
zation and anaphylaxis).
ELI SA
Analysis of mMCP1, mouse IL-4, OVA-specic IgE, IgG1,
and IgG2a were performed as described previously (Oyoshi
et al., 2011; Bartnikas et al., 2013). Biotin-conjugated peanut
extract or egg white extract (Greer) was used to detect pea-
nut- or egg white–specic IgE. TGF-β1 was measured per
the manufacturer’s instructions (Aymetrix). For analysis of
OVA-IgG1 and OVA-IgG2a immune complexes or free OVA,
ELI SA plates were coated with goat anti-OVA polyclonal an-
tibody (MP Biomedicals), saturated nonspecic binding, and
incubated with serum or breast milk, followed by incubation
with biotin-conjugated anti–mouse IgG1 or IgG2a antibod-
ies (BD) or rabbit anti-OVA polyclonal antibody (Abcam).
HRP-conjugated avidin (Aymetrix) was used for detection.
As a reference standard, adjacent wells on the same plates were
coated with OVA (grade V, Sigma), and anti-OVA mouse IgG1
(Sigma) or anti-OVA mouse IgG2a (Biolegend) were added.
For analysis of human OVA-IgG4 or OVA-IgG4 immune
complexes, ELI SA plates were coated with OVA or goat anti-
OVA antibody and incubated with breast milk followed by
biotin-conjugated anti–human IgG4 (BD Biosciences) with
total human IgG4 as a reference standard.
Cell cultures
Allergen-specic T cells were identied by allergen-induced
ex vivo proliferation as previously described (Burton et al.,
2014b). In brief, MLN cells were labeled with CellTrace Vio-
let (Life Technologies) and cultured in complete RPMI 1640
(Invitrogen) supplemented by 10% FCS, 0.05 mM 2-mer-
captoethanol, and penicillin/streptomycin with or without
allergen (200 µg/ml OVA or peanut extract) for 5 d. Cells
undergoing proliferation (dye dilution) were considered aller-
gen-specic, a conclusion supported by a lack of proliferation
in the absence of allergen or in allergen-stimulated cells from
unsensitized mice. For OVA-specic T reg cell dierentiation,
CD11c+ DCs were enriched from MLN of 3–5-wk-old WT
or
Fcgrt
/
mice by CD11c+ Microbeads (Miltenyi). Naive
WT mice or ospring of epicutaneously sensitized mothers
with saline or OVA 1 day after last maternal exposure (day 46;
Fig.1A) were used. Naive CD4+ T cells were enriched from
spleen of
DO11.10+Rag2
/
Foxp3EGFP
mice by a naive CD4+
T cell kit (Miltenyi). Naive CD4+ T cells (2.5 × 105) were
cultured with CD11c+ DCs (0.5 × 105) in the presence or ab-
sence of 40× diluted breast milk, or 1µM OVA323-339 peptide
and 5 ng/ml recombinant human TGF-β1 (R&D Systems).
After 3 d, allergen-specic induced T reg cells were analyzed
by ow cytometry on the basis of EGFP uorescence.
Adoptive transfer
CD11c+ DCs were enriched as above (Cell cultures) from
MLN of ospring. CD11c+ DCs (2 × 105) and naive CD4+-
DO11.10+Foxp3EGFP- T cells (2 × 106) prepared as above
(Cell cultures) were injected intravenously into naive recipi-
ents. After 5 d, recipients were epicutaneously sensitized over
9 d, then orally challenged with OVA as above (Allergen sen-
sitization and anaphylaxis).
Suppression assay
CD4+CD25+ T reg cells isolated by magnetic beads (Miltenyi)
from MLN of BALB/c WT ospring were cocultured with
naive CD4+ T cells isolated from
DO11.10+Rag2
/
Foxp3EGFP
mice (2.5 × 104 cells/well) labeled with CellTrace Violet at
Maternal immune complexes form neonatal tolerance | Ohsaki et al.110
1:1 T reg/responder ratio in the presence of 1µM OVA323-339
peptide and irradiated splenocytes (5 × 104 cells/well). After 4
d, cell proliferation was evaluated by dye dilution. The percent
suppression was calculated using the following for mula:
1  −  
(
% of proliferated cells with T reg present
_______________________________
% of proliferated cells without T reg present
)
× 100.
Flow cytometry
T reg cells were stained with uorochrome-conjugated an-
tibodies for Foxp3, CD3, CD4, and CD25 using the Foxp3
staining kit (eBioscience). For lamina propria lymphocyte iso-
lation, a jejunum section of the small intestine was harvested,
and the tissue was prepared as previously described (Galand
et al., 2016). Single-cell suspensions were stained with uoro-
chrome-conjugated mAbs for IgE, c-kit, CD3, CD11c, CD19,
CD45, and NKp46 (purchased from BioLegend, BD Biosci-
ences, or eBioscience). Dead cells were routinely excluded
from analysis by Fixable Viability Dye staining (eBioscience).
Mouse mast cells were identied as live, CD45+linc-kit+IgE+
cells. Cells were analyzed on LSRFortessa (BD), and the data
were analyzed using FlowJo software (Tree Star Inc.).
Quantitative PCR
Quantitative real-time PCR was performed as described pre-
viously (Oyoshi et al., 2011).
Statistical analysis
A Mann-Whitney
U
test (between two groups) or nonpara-
metric one-way ANO VA (between multiple groups) was
used to compare the distribution of each outcome. All analy-
ses were performed with Prism software, version 6.0 (Graph-
Pad Software). A p-value of <0.05 was considered to indicate
statistical signicance.
Online supplemental material
Fig. S1 shows that maternal sensitization protects ospring
from peanut allergy. Fig. S2 shows the contribution of in
utero transferred maternal IgG-IC to induction of neona-
tal tolerance. Fig. S3 shows maternal sensitization induces
long-lasting protection in ospring. Fig. S4 summarizes
the mechanisms of neonatal tolerance via a maternal
IgG-IC-FcRn axis. Table S1 summarizes the characteris-
tics of human breast milk.
ACKNOWLEDGMENTS
We thank Dr. Talal A. Chatila for his kind gifts of
Foxp3
EGFP/DTR+
and
DO11.10
+
Rag2
/
Foxp3
EGFP
mice and scientic discussion. We thank Dr. Hans C. Oettgen for scientic
advice and reading the manuscript, Ms. Kimberly H. Barbas for facilitating clinical
sample collection, and Ms. Shelly Zing Chin Lum and Ms. Jacqueline Beaupre for
technical assistance.
This work was supported by the Food Allergy Research and Education (FARE),
the HOPE APF ED/ARTrust Pilot Grant, the William F. Milton Fund, the Harvard Catalyst
Clinical and Translational Research Center (NCA TS grant no. 8UL 1TR000170), and the
Boston Children’s Hospital Pediatric Associates Award to M.K. Oyoshi and a National
Institutes of Health grant (no. DK053056) and a Harvard Digestive Diseases Center
grant (no. P30DK034854) to R.S. Blumberg.
R.S. Blumberg consults for and has received equity in Syntimmune Pharma-
ceuticals, which is developing therapies that target FcRn. The rest of the authors
declare no competing nancial interests.
Author contributions: A. Ohsaki, N. Venturelli, and M.K. Oyoshi designed and
performed the experiments; T.M. Buccigrosso, S.K. Osganian, J. Lee, and M.K. Oyoshi
collected clinical samples; R.S. Blumberg provided critical mice; and A. Ohsaki,
R.S. Blumberg, and M.K. Oyoshi wrote the manuscript.
Submitted: 29 June 2017
Revised: 24 August 2017
Accepted: 28 September 2017
REFERENCES
Akdis, C.A., and M. Akdis. 2011. Mechanisms of allergen-specic
immunotherapy. J. Allergy Clin. Immunol. 127:18–27. https ://doi .org /10
.1016 /j .jaci .2010 .11 .030
Akilesh, S., T.B. Huber, H. Wu, G. Wang, B. Hartleben, J.B. Kopp, J.H. Miner,
D.C. Roopenian, E.R. Unanue, and A.S. Shaw. 2008. Podocytes use FcRn
to clear IgG from the glomerular basement membrane. Proc. Natl. Acad.
Sci. USA. 105:967–972. https ://doi .org /10 .1073 /pnas .0711515105
Antohe, F., L. Rădulescu, A. Gafencu, V. Gheţie, and M. Simionescu.
2001. Expression of functionally active FcRn and the dierentiated
bidirectional transport of IgG in human placental endothelial cells. Hum.
Immunol. 62:93–105. https ://doi .org /10 .1016 /S0198 -8859(00)00244 -5
Bai, Y., L. Ye, D.B. Tesar, H. Song, D. Zhao, P.J. Björkman, D.C. Roopenian, and
X. Zhu. 2011. Intracellular neutralization of viral infection in polarized
epithelial cells by neonatal Fc receptor (FcRn)-mediated IgG transport.
Proc. Natl. Acad. Sci. USA. 108:18406–18411. https ://doi .org /10 .1073 /
pnas .1115348108
Baker, K., S.W. Qiao, T.T. Kuo, V.G. Aveson, B. Platzer, J.T. Andersen, I. Sandlie,
Z. Chen, C. de Haar, W.I. Lencer, et al. 2011. Neonatal Fc receptor for
IgG (FcRn) regulates cross-presentation of IgG immune complexes by
CD8-CD11b+ dendritic cells. Proc. Natl. Acad. Sci. USA. 108:9927–
9932. https ://doi .org /10 .1073 /pnas .1019037108
Baker, K., T. Rath, M.B. Flak, J.C. Arthur, Z. Chen, J.N. Glickman, I. Zlobec,
E. Karamitopoulou, M.D. Stachler, R.D. Odze, et al. 2013. Neonatal
Fc receptor expression in dendritic cells mediates protective immunity
against colorectal cancer. Immunity. 39:1095–1107. https ://doi .org /10
.1016 /j .immuni .2013 .11 .003
Baker, K., T. Rath, M. Pyzik, and R.S. Blumberg. 2014. The Role of FcRn
in Antigen Presentation. Front. Immunol. 5:408. https ://doi .org /10 .3389
/fimmu .2014 .00408
Bartnikas, L.M., M.F. Gurish, O.T. Burton, S. Leisten, E. Janssen, H.C. Oettgen,
J. Beaupre, C.N. Lewis, K.F. Austen, S. Schulte, et al. 2013. Epicutaneous
sensitization results in IgE-dependent intestinal mast cell expansion and
food-induced anaphylaxis. J. Allergy Clin. Immunol. 131:451–460. https ://
doi .org /10 .1016 /j .jaci .2012 .11 .032
Bernard, H., S. Ah-Leung, M.F. Drumare, C. Feraudet-Tarisse, V. Verhasselt,
J.M. Wal, C. Créminon, and K. Adel-Patient. 2014. Peanut allergens are
rapidly transferred in human breast milk and can prevent sensitization in
mice. Allergy. 69:888–897. https ://doi .org /10 .1111 /all .12411
Brambell, F.W. 1969. The transmission of immune globulins from the mother
to the foetal and newborn young. Proc. Nutr. Soc. 28:35–41. https ://doi
.org /10 .1079 /PNS19690007
Brough, H.A., A. Simpson, K. Makinson, J. Hankinson, S. Brown, A. Douir i,
D.C. Belgrave, M. Penagos, A.C. Stephens, W.H. McLean, et al. 2014.
Peanut allergy: eect of environmental peanut exposure in children with
laggrin loss-of-function mutations. J. Allergy Clin. Immunol. 134:867–
875. https ://doi .org /10 .1016 /j .jaci .2014 .08 .011
111JEM Vol. 215, No. 1
Brown, S.J., Y. Asai, H.J. Cordell, L.E. Campbell, Y. Zhao, H. Liao, K.
Northstone, J. Henderson, R. Alizadehfar, M. Ben-Shoshan, et al. 2011.
Loss-of-function variants in the laggrin gene are a signicant risk
factor for peanut allergy. J. Allergy Clin. Immunol. 127:661–667. https ://
doi .org /10 .1016 /j .jaci .2011 .01 .031
Bunyavanich, S., S.L. Rifas-Shiman, T.A. Platts-Mills, L. Workman, J.E.
Sordillo, C.A. Camargo Jr., M.W. Gillman, D.R. Gold, and A.A. Litonjua.
2014. Peanut, milk, and wheat intake during pregnancy is associated
with reduced allergy and asthma in children. J. Allergy Clin. Immunol.
133:1373–1382. https ://doi .org /10 .1016 /j .jaci .2013 .11 .040
Burton, O.T., S.L. Logsdon, J.S. Zhou, J. Medina-Tamayo, A. Abdel-Gadir, M.
Noval Rivas, K.J. Koleoglou, T.A. Chatila, L.C. Schneider, R. Rachid, et
al. 2014a. Oral immunotherapy induces IgG antibodies that act through
FcgammaRIIb to suppress IgE-mediated hypersensitivity. J. Allergy Clin.
Immunol. 134:1310–1317. https ://doi .org /10 .1016 /j .jaci .2014 .05 .042
Burton, O.T., M. Noval Rivas, J.S. Zhou, S.L. Logsdon, A.R. Darling, K.J.
Koleoglou, A. Roers, H. Houshyar, M.A. Crackower, T.A. Chatila, and
H.C. Oettgen. 2014b. Immunoglobulin E signal inhibition during
allergen ingestion leads to reversal of established food allergy and
induction of regulatory T cells. Immunity. 41:141–151. https ://doi .org
/10 .1016 /j .immuni .2014 .05 .017
Burton, O.T., J.M. Tamayo, A.J. Stranks, K.J. Koleoglou, and H.C. Oettgen.
2017. Allergen-specic IgG antibodies signaling via FcgammaRIIb
promote food tolerance. J. Allergy Clin. Immunol. https ://doi .org /10
.1016 /j .jaci .2017 .03 .045
Caubet, J.C., R. Bencharitiwong, E. Moshier, J.H. Godbold, H.A. Sampson,
and A. Nowak-Węgrzyn. 2012. Signicance of ovomucoid- and
ovalbumin-specic IgE/IgG(4) ratios in egg allergy. J. Allergy Clin.
Immunol. 129:739–747. https ://doi .org /10 .1016 /j .jaci .2011 .11 .053
Chatila, T.A. 2005. Role of regulatory T cells in human diseases. J. Allergy Clin.
Immunol. 116:949–959. https ://doi .org /10 .1016 /j .jaci .2005 .08 .047
Chaudhury, C., S. Mehnaz, J.M. Robinson, W.L. Hayton, D.K. Pearl, D.C.
Roopenian, and C.L. Anderson. 2003. The major histocompatibility
complex-related Fc receptor for IgG (FcRn) binds albumin and
prolongs its lifespan. J. Exp. Med. 197:315–322. https ://doi .org /10 .1084
/jem .20021829
Claypool, S.M., B.L. Dickinson, M. Yoshida, W.I. Lencer, and R.S. Blumberg.
2002. Functional reconstitution of human FcRn in Madin-Darby canine
kidney cells requires co-expressed human beta 2-microglobulin. J. Biol.
Chem. 277:28038–28050. https ://doi .org /10 .1074 /jbc .M202367200
Curotto de Lafaille, M.A., N. Kutchukhidze, S. Shen, Y. Ding, H. Yee, and
J.J. Lafaille. 2008. Adaptive Foxp3+ regulatory T cell-dependent and
-independent control of allergic inammation. Immunity. 29:114–126.
https ://doi .org /10 .1016 /j .immuni .2008 .05 .010
De Groot, A.S., and W. Martin. 2009. Reducing risk, improving outcomes:
bioengineering less immunogenic protein therapeutics. Clin. Immunol.
131:189–201. https ://doi .org /10 .1016 /j .clim .2009 .01 .009
De Groot, A.S., L. Moise, J.A. McMurry, E. Wambre, L. Van Overtvelt, P.
Moingeon, D.W. Scott, and W. Martin. 2008. Activation of natural
regulatory T cells by IgG Fc-derived peptide “Tregitopes”. Blood.
112:3303–3311. https ://doi .org /10 .1182 /blood -2008 -02 -138073
Dickinson, B.L., K. Badizadegan, Z. Wu, J.C. Ahouse, X. Zhu, N.E. Simister,
R.S. Blumberg, and W.I. Lencer. 1999. Bidirectional FcRn-dependent
IgG transport in a polarized human intestinal epithelial cell line. J. Clin.
Invest. 104:903–911. https ://doi .org /10 .1172 /JCI6968
Dickinson, B.L., S.M. Claypool, J.A. D’Angelo, M.L. Aiken, N. Venu, E.H.
Yen, J.S. Wagner, J.A. Borawski, A.T. Pierce, R. Hershberg, et al. 2008.
Ca2+-dependent calmodulin binding to FcRn aects immunoglobulin
G transport in the transcytotic pathway. Mol. Biol. Cell. 19:414–423. https
://doi .org /10 .1091 /mbc .E07 -07 -0658
Eigenmann, P.A., S.H. Sicherer, T.A. Borkowski, B.A. Cohen, and H.A.
Sampson. 1998. Prevalence of IgE-mediated food allergy among children
with atopic dermatitis. Pediatrics. 101:E8. https ://doi .org /10 .1542 /peds
.101 .3 .e8
Frazier, A.L., C.A. Camargo Jr., S. Malspeis, W.C. Willett, and M.C. Young.
2014. Prospective study of peripregnancy consumption of peanuts
or tree nuts by mothers and the risk of peanut or tree nut allergy in
their ospring. JAMA Pediatr. 168:156–162. https ://doi .org /10 .1001 /
jamapediatrics .2013 .4139
Fusaro, A.E., M. Maciel, J.R. Victor, C.R. Oliveira, A.J. Duarte, and M.N.
Sato. 2002. Inuence of maternal murine immunization with
Dermatophagoides pteronyssinus extract on the type I hypersensitivity
response in ospring. Int. Arch. Allergy Immunol. 127:208–216. https ://
doi .org /10 .1159 /000053865
Fusaro, A.E., C.A. Brito, J.R. Victor, P.O. Rigato, A.L. Goldoni, A.J. Duarte,
and M.N. Sato. 2007. Maternal-fetal interaction: preconception
immunization in mice prevents neonatal sensitization induced by
allergen exposure during pregnancy and breastfeeding. Immunology.
122:107–115. https ://doi .org /10 .1111 /j .1365 -2567 .2007 .02618 .x
Galand, C., J.M. Leyva-Castillo, J. Yoon, A. Han, M.S. Lee, A.N. McKenzie,
M. Stassen, M.K. Oyoshi, F.D. Finkelman, and R.S. Geha. 2016. IL-33
promotes food anaphylaxis in epicutaneously sensitized mice by
targeting mast cells. J. Allergy Clin. Immunol. 138:1356–1366. https ://doi
.org /10 .1016 /j .jaci .2016 .03 .056
Gill, R.K., S. Mahmood, C.P. Sodhi, J.P. Nagpaul, and A. Mahmood. 1999.
IgG binding and expression of its receptor in rat intestine during post-
natal development. Indian J. Biochem. Biophys. 36:252–257.
Gri, G., S. Piconese, B. Frossi, V. Manfroi, S. Merluzzi, C. Tripodo, A. Viola, S.
Odom, J. Rivera, M.P. Colombo, and C.E. Pucillo. 2008. CD4+CD25+
regulatory T cells suppress mast cell degranulation and allergic responses
through OX40-OX40L interaction. Immunity. 29:771–781. https ://doi
.org /10 .1016 /j .immuni .2008 .08 .018
Guilliams, M., P. Bruhns, Y. Saeys, H. Hammad, and B.N. Lambrecht. 2014.
The function of Fcγ receptors in dendritic cells and macrophages. Nat.
Rev. Immunol. 14:94–108. https ://doi .org /10 .1038 /nri3582
Haribhai, D., J.B. Williams, S. Jia, D. Nickerson, E.G. Schmitt, B. Edwards, J.
Ziegelbauer, M. Yassai, S.H. Li, L.M. Relland, et al. 2011. A requisite role
for induced regulatory T cells in tolerance based on expanding antigen
receptor diversity. Immunity. 35:109–122. https ://doi .org /10 .1016 /j
.immuni .2011 .03 .029
Hill, D.J., R.G. Heine, C.S. Hosking, J. Brown, L. Thiele, K.J. Allen, J. Su,
G. Varigos, and J.B. Carlin. 2007. IgE food sensitization in infants with
eczema attending a dermatology department. J. Pediatr. 151:359–363.
https ://doi .org /10 .1016 /j .jpeds .2007 .04 .070
Hirose, J., S. Ito, N. Hirata, S. Kido, N. Kitabatake, and H. Narita. 2001.
Occurrence of the major food allergen, ovomucoid, in human breast
milk as an immune complex. Biosci. Biotechnol. Biochem. 65:1438–1440.
https ://doi .org /10 .1271 /bbb .65 .1438
Hochwallner, H., J. Alm, C. Lupinek, C. Johansson, A. Mie, A. Scheynius, and
R. Valenta. 2014. Transmission of allergen-specic IgG and IgE from
maternal blood into breast milk visualized with microarray technology.
J. Allergy Clin. Immunol. 134:1213–1215. https ://doi .org /10 .1016 /j .jaci
.2014 .08 .041
Husby, S., V.A. Oxelius, B. Teisner, J.C. Jensenius, and S.E. Svehag. 1985.
Humoral immunity to dietary antigens in healthy adults. Occur rence,
isotype and IgG subclass distribution of serum antibodies to protein
antigens. Int. Arch. Allergy Appl. Immunol. 77:416–422. https ://doi .org /10
.1159 /000233819
James, L.K., H. Bowen, R.A. Calvert, T.S. Dodev, M.H. Shamji, A.J. Beavil,
J.M. McDonnell, S.R. Durham, and H.J. Gould. 2012. Allergen
specicity of IgG(4)-expressing B cells in patients with grass pollen
allergy undergoing immunotherapy. J. Allergy Clin. Immunol. 130:663–
670. https ://doi .org /10 .1016 /j .jaci .2012 .04 .006
Maternal immune complexes form neonatal tolerance | Ohsaki et al.112
Jarrett, E., and E. Hall. 1979. Selective suppression of IgE antibody
responsiveness by maternal inuence. Nature. 280:145–147. https ://doi
.org /10 .1038 /280145a0
Kaiserlian, D., K. Vidal, and J.P. Revillard. 1989. Murine enterocytes can
present soluble antigen to specic class II-restricted CD4+ T cells. Eu r. J.
Immunol. 19:1513–1516. https ://doi .org /10 .1002 /eji .1830190827
Karlsson, M.R., J. Rugtveit, and P. Brandtzaeg. 2004. Allergen-responsive
CD4+CD25+ regulatory T cells in children who have outgrown cow’s
milk allergy. J. Exp. Med. 199:1679–1688. https ://doi .org /10 .1084 /jem
.20032121
Lack, G., D. Fox, K. Northstone, and J. Golding. Avon Longitudinal Study
of Parents and Children Study Team. 2003. Factors associated with the
development of peanut allergy in childhood. N. Engl. J. Med. 348:977–
985. https ://doi .org /10 .1056 /NEJMoa013536
Leach, J.L., D.D. Sedmak, J.M. Osborne, B. Rahill, M.D. Lair more, and C.L.
Anderson. 1996. Isolation from human placenta of the IgG transporter,
FcRn, and localization to the syncytiotrophoblast: implications for ma-
ternal-fetal antibody transport. J. Immunol. 157:3317–3322.
Lei, T.C., and D.W. Scott. 2005. Induction of tolerance to factor VIII inhibitors
by gene therapy with immunodominant A2 and C2 domains presented
by B cells as Ig fusion proteins. Blood. 105:4865–4870. https ://doi .org
/10 .1182 /blood -2004 -11 -4274
Leme, A.S., C. Hubeau, Y. Xiang, A. Goldman, K. Hamada, Y. Suzaki, and
L. Kobzik. 2006. Role of breast milk in a mouse model of maternal
transmission of asthma susceptibility. J. Immunol. 176:762–769. https ://
doi .org /10 .4049 /jimmunol .176 .2 .762
Li, Z., S. Palaniyandi, R. Zeng, W. Tuo, D.C. Roopenian, and X. Zhu. 2011.
Transfer of IgG in the female genital tract by MHC class I-related
neonatal Fc receptor (FcRn) confers protective immunity to vaginal
infection. Proc. Natl. Acad. Sci. USA. 108:4388–4393. https ://doi .org /10
.1073 /pnas .1012861108
Littman, D.R., and A.Y. Rudensky. 2010. Th17 and regulatory T cells in
mediating and restraining inammation. Cell. 140:845–858. https ://doi
.org /10 .1016 /j .cell .2010 .02 .021
Liu, X., L. Lu, Z. Yang, S. Palaniyandi, R. Zeng, L.Y. Gao, D.M. Mosser, D.C.
Roopenian, and X. Zhu. 2011. The neonatal FcR-mediated presentation
of immune-complexed antigen is associated with endosomal and
phagosomal pH and antigen stability in macrophages and dendritic
cells. J. Immunol. 186:4674–4686. https ://doi .org /10 .4049 /jimmunol
.1003584
López-Expósito, I., Y. Song, K.M. Järvinen, K. Srivastava, and X.M. Li. 2009.
Maternal peanut exposure during pregnancy and lactation reduces
peanut allergy risk in ospring. J. Allergy Clin. Immunol. 124:1039–1046.
https ://doi .org /10 .1016 /j .jaci .2009 .08 .024
Matson, A.P., R.S. Thrall, E. Rafti, and L. Puddington. 2009. Breastmilk from
allergic mothers can protect ospring from allergic airway inammation.
Breastfeed. Med. 4:167–174. https ://doi .org /10 .1089 /bfm .2008 .0130
Metcalfe, D.D., R.D. Peavy, and A.M. Gilllan. 2009. Mechanisms of mast
cell signaling in anaphylaxis. J. Allergy Clin. Immunol. 124:639–646, quiz
:647–648. https ://doi .org /10 .1016 /j .jaci .2009 .08 .035
Montoyo, H.P., C. Vaccaro, M. Hafner, R.J. Ober, W. Mueller, and E.S. Ward.
2009. Conditional deletion of the MHC class I-related receptor FcRn
reveals the sites of IgG homeostasis in mice. Proc. Natl. Acad. Sci. USA.
106:2788–2793. https ://doi .org /10 .1073 /pnas .0810796106
Mosconi, E., A. Rekima, B. Seitz-Polski, A. Kanda, S. Fleury, E. Tissandie,
R. Monteiro, D.D. Dombrowicz, V. Julia, N. Glaichenhaus, and V.
Verhasselt. 2010. Breast milk immune complexes are potent inducers
of oral tolerance in neonates and prevent asthma development. Mucosal
Immunol. 3:461–474. https ://doi .org /10 .1038 /mi .2010 .23
Mousallem, T., and A.W. Burks. 2012. Immunology in the Clinic Review
Series; focus on allergies: immunotherapy for food allergy. Clin. Exp.
Immunol. 167:26–31. https ://doi .org /10 .1111 /j .1365 -2249 .2011
.04499 .x
Nakajima, S., B.Z. Igyarto, T. Honda, G. Egawa, A. Otsuka, M. Hara-Chikuma,
N. Watanabe, S.F. Ziegler, M. Tomura, K. Inaba, et al. 2012. Langerhans
cells are critical in epicutaneous sensitization with protein antigen via
thymic stromal lymphopoietin receptor signaling. J. Allergy Clin. Immunol.
129:1048–1055. https ://doi .org /10 .1016 /j .jaci .2012 .01 .063
Noval Rivas, M., O.T. Burton, P. Wise, L.M. Charbonnier, P. Georgiev,
H.C. Oettgen, R. Rachid, and T.A. Chatila. 2015. Regulatory T cell
reprogramming toward a Th2-cell-like lineage impairs oral tolerance and
promotes food allergy. Immunity. 42:512–523. https ://doi .org /10 .1016 /j
.immuni .2015 .02 .004
Ohkura, N., Y. Kitagawa, and S. Sakaguchi. 2013. Development and
maintenance of regulatory T cells. Immunity. 38:414–423. https ://doi .org
/10 .1016 /j .immuni .2013 .03 .002
Oyoshi, M.K., A. Elkhal, J.E. Scott, M.A. Wurbel, J.L. Hornick, J.J. Campbell,
and R.S. Geha. 2011. Epicutaneous challenge of orally immunized mice
redirects antigen-specic gut-homing T cells to the skin. J. Clin. Invest.
121:2210–2220. https ://doi .org /10 .1172 /JCI43586
Oyoshi, M.K., H.C. Oettgen, T.A. Chatila, R.S. Geha, and P.J. Bryce. 2014.
Food allergy: Insights into etiology, prevention, and treatment provided
by murine models. J. Allergy Clin. Immunol. 133:309–317. https ://doi .org
/10 .1016 /j .jaci .2013 .12 .1045
Perkin, M.R., K. Logan, A. Tseng, B. Raji, S. Ayis, J. Peacock, H. Brough, T.
Marrs, S. Radulovic, J. Craven, et al. EAT Study Team. 2016. Randomized
Trial of Introduction of Allergenic Foods in Breast-Fed Infants. N. Engl. J.
Med. 374:1733–1743. https ://doi .org /10 .1056 /NEJMoa1514210
Pyzik, M., T. Rath, W.I. Lencer, K. Baker, and R.S. Blumberg. 2015. FcRn:
The Architect Behind the Immune and Nonimmune Functions of IgG
and Albumin. J. Immunol. 194:4595–4603. https ://doi .org /10 .4049 /
jimmunol .1403014
Qiao, S.W., K. Kobayashi, F.E. Johansen, L.M. Sollid, J.T. Andersen, E. Milford,
D.C. Roopenian, W.I. Lencer, and R.S. Blumberg. 2008. Dependence of
antibody-mediated presentation of antigen on FcRn. Proc. Natl. Acad. Sci.
USA. 105:9337–9342. https ://doi .org /10 .1073 /pnas .0801717105
Rath, T., K. Baker, J.A. Dumont, R.T. Peters, H. Jiang, S.W. Qiao, W.I. Lencer,
G.F. Pierce, and R.S. Blumberg. 2015. Fc-fusion proteins and FcRn:
structural insights for longer-lasting and more eective therapeutics.
Crit. Rev. Biotechnol. 35:235–254. https ://doi .org /10 .3109 /07388551
.2013 .834293
Rekima, A., P. Macchiaver ni, M. Turfkruyer, S. Holvoet, L. Dupuis, N. Baiz, I.
Annesi-Maesano, A. Mercenier, S. Nutten, and V. Verhasselt. 2017. Long-
term reduction in food allergy susceptibility in mice by combining
breastfeeding-induced tolerance and TGF-β-enriched formula after
weaning. Clin. Exp. Allergy. 47:565–576. https ://doi .org /10 .1111 /cea
.12864
Renz, H., P. Brandtzaeg, and M. Hornef. 2011. The impact of per inatal immune
development on mucosal homeostasis and chronic inammation. Nat.
Rev. Immunol. 12:9–23. https ://doi .org /10 .1038 /nri3112
Roopenian, D.C., G.J. Chr istianson, T.J. Sproule, A.C. Brown, S. Akilesh, N.
Jung, S. Petkova, L. Avanessian, E.Y. Choi, D.J. Shaer, et al. 2003. The
MHC class I-like IgG receptor controls perinatal IgG transport, IgG
homeostasis, and fate of IgG-Fc-coupled drugs. J. Immunol. 170:3528–
3533. https ://doi .org /10 .4049 /jimmunol .170 .7 .3528
Rumbo, M., F.G. Chirdo, M.C. Añón, and C.A. Fossati. 1998. Detection
and characterization of antibodies specic to food antigens (gliadin,
ovalbumin and beta-lactoglobulin) in human serum, saliva, colostrum
and milk. Clin. Exp. Immunol. 112:453–458. https ://doi .org /10 .1046 /j
.1365 -2249 .1998 .00587 .x
Scadding, G.W., M.H. Shamji, M.R. Jacobson, D.I. Lee, D. Wilson, M.T.
Lima, L. Pitkin, C. Pilette, K. Nouri-Ar ia, and S.R. Durham. 2010.
Sublingual grass pollen immunotherapy is associated with increases
in sublingual Foxp3-expressing cells and elevated allergen-specic
immunoglobulin G4, immunoglobulin A and serum inhibitory activity
for immunoglobulin E-facilitated allergen binding to B cells. Clin. Exp.
113JEM Vol. 215, No. 1
Allergy. 40:598–606. https ://doi .org /10 .1111 /j .1365 -2222 .2010 .03462
.x
Schroeder, H.W. Jr., and L. Cavacini. 2010. Structure and function of
immunoglobulins. J. Allergy Clin. Immunol. 125(2, Suppl 2):S41–S52.
https ://doi .org /10 .1016 /j .jaci .2009 .09 .046
Schwarz, A., V. Panetta, A. Cappella, S. Hofmaier, L. Hatzler, A. Rohrbach, O.
Tsilochristou, C.P. Bauer, U. Homann, J. Forster, et al. 2016. IgG and
IgG4 to 91 allergenic molecules in early childhood by route of exposure
and current and future IgE sensitization: Results from the Multicentre
Allergy Study birth cohort. J. Allergy Clin. Immunol. 138:1426–1433.
https ://doi .org /10 .1016 /j .jaci .2016 .01 .057
Scott, D.W., and A.S. De Groot. 2010. Can we prevent immunogenicity of
human protein drugs? Ann. Rheum. Dis. 69(Suppl 1):i72–i76. https ://doi
.org /10 .1136 /ard .2009 .117564
Shreer, W.G., N. Wanich, M. Moloney, A. Nowak-Wegrzyn, and H.A.
Sampson. 2009. Association of allergen-specic regulatory T cells with
the onset of clinical tolerance to milk protein. J. Allergy Clin. Immunol.
123:43–52. https ://doi .org /10 .1016 /j .jaci .2008 .09 .051
Sicherer, S.H., and H.A. Sampson. 1999. Food hypersensitivity and atopic
dermatitis: pathophysiology, epidemiology, diagnosis, and management. J.
Allergy Clin. Immunol. 104:S114–S122. https ://doi .org /10 .1016 /S0091
-6749(99)70053 -9
Sicherer, S.H., and H.A. Sampson. 2014. Food allergy: Epidemiology,
pathogenesis, diagnosis, and treatment. J. Allergy Clin. Immunol. 133:291–
307. https ://doi .org /10 .1016 /j .jaci .2013 .11 .020
Sicherer, S.H., A.W. Burks, and H.A. Sampson. 1998. Clinical features of
acute allergic reactions to peanut and tree nuts in children. Pediatrics.
102:e6. https ://doi .org /10 .1542 /peds .102 .1 .e6
Sicherer, S.H., R.A. Wood, D. Stablein, R. Lindblad, A.W. Burks, A.H. Liu,
S.M. Jones, D.M. Fleischer, D.Y. Leung, and H.A. Sampson. 2010.
Maternal consumption of peanut during pregnancy is associated with
peanut sensitization in atopic infants. J. Allergy Clin. Immunol. 126:1191–
1197. https ://doi .org /10 .1016 /j .jaci .2010 .08 .036
Simister, N.E., and K.E. Mostov. 1989. An Fc receptor structurally related
to MHC class I antigens. Nature. 337:184–187. https ://doi .org /10 .1038
/337184a0
Simister, N.E., C.M. Story, H.L. Chen, and J.S. Hunt. 1996. An IgG-
transporting Fc receptor expressed in the syncytiotrophoblast of human
placenta. Eur. J. Immunol. 26:1527–1531. https ://doi .org /10 .1002 /eji
.1830260718
Skripak, J.M., S.D. Nash, H. Rowley, N.H. Brereton, S. Oh, R.G. Hamilton,
E.C. Matsui, A.W. Burks, and R.A. Wood. 2008. A randomized, double-
blind, placebo-controlled study of milk oral immunotherapy for cow’s
milk allergy. J. Allergy Clin. Immunol. 122:1154–1160. https ://doi .org /10
.1016 /j .jaci .2008 .09 .030
Spiekermann, G.M., P.W. Finn, E.S. Ward, J. Dumont, B.L. Dickinson, R.S.
Blumberg, and W.I. Lencer. 2002. Receptor-mediated immunoglobulin
G transport across mucosal barriers in adult life: functional expression of
FcRn in the mammalian lung. J. Exp. Med. 196:303–310. https ://doi .org
/10 .1084 /jem .20020400
Syed, A., M.A. Garcia, S.C. Lyu, R. Bucayu, A. Kohli, S. Ishida, J.P. Berglund, M.
Tsai, H. Maecker, G. O’Riordan, et al. 2014. Peanut oral immunotherapy
results in increased antigen-induced regulatory T-cell function and
hypomethylation of forkhead box protein 3 (FOXP3). J. Allergy Clin.
Immunol. 133:500–510. https ://doi .org /10 .1016 /j .jaci .2013 .12 .1037
Till, S.J., J.N. Francis, K. Nouri-Aria, and S.R. Durham. 2004. Mechanisms
of immunotherapy. J. Allergy Clin. Immunol. 113:1025–1034. https ://doi
.org /10 .1016 /j .jaci .2004 .03 .024
Utho, H., A. Spenner, W. Reckelkamm, B. Ahrens, G. Wölk, R. Hackler, F.
Hardung, J. Schaefer, A. Scheold, H. Renz, and U. Herz. 2003. Critical
role of preconceptional immunization for protective and nonpathological
specic immunity in murine neonates. J. Immunol. 171:3485–3492. https
://doi .org /10 .4049 /jimmunol .171 .7 .3485
Valenta, R., H. Hochwallner, B. Linhart, and S. Pahr. 2015. Food allergies:
the basics. Gastroenterology. 148:1120–1131. https ://doi .org /10 .1053 /j
.gastro .2015 .02 .006
van Wijk, F., E.J. Wehrens, S. Nierkens, L. Boon, A. Kasran, R. Pieters, and
L.M. Knippels. 2007. CD4+CD25+ T cells regulate the intensity of
hypersensitivity responses to peanut, but are not decisive in the induction
of oral sensitization. Clin. Exp. Allergy. 37:572–581. https ://doi .org /10
.1111 /j .1365 -2222 .2007 .02681 .x
Venturelli, N., W.S. Lexmond, A. Ohsaki, S. Nurko, H. Karasuyama, E. Fiebiger,
and M.K. Oyoshi. 2016. Allergic skin sensitization promotes eosinophilic
esophagitis via the IL-33-basophil axis in mice. J. Allergy Clin. Immunol.
138:1367–1380.e5. https ://doi .org /10 .1016 /j .jaci .2016 .02 .034
Verhasselt, V. 2010a. Neonatal tolerance under breastfeeding inuence. Cur r.
Opin. Immunol. 22:623–630. https ://doi .org /10 .1016 /j .coi .2010 .08 .008
Verhasselt, V. 2010b. Oral tolerance in neonates: from basics to potential
prevention of allergic disease. Mucosal Immunol. 3:326–333. https ://doi
.org /10 .1038 /mi .2010 .25
Wachholz, P.A., and S.R. Durham. 2004. Mechanisms of immunotherapy:
IgG revisited. Curr. Opin. Allergy Clin. Immunol. 4:313–318. https ://doi
.org /10 .1097 /01 .all .0000136753 .35948 .c0
Williams, C.M., and S.J. Galli. 2000. Mast cells can amplify airway reactivity
and features of chronic inammation in an asthma model in mice. J. E xp.
Med. 192:455–462. https ://doi .org /10 .1084 /jem .192 .3 .455
Yoshida, M., S.M. Claypool, J.S. Wagner, E. Mizoguchi, A. Mizoguchi, D.C.
Roopenian, W.I. Lencer, and R.S. Blumberg. 2004. Human neonatal Fc
receptor mediates transport of IgG into luminal secretions for delivery
of antigens to mucosal dendritic cells. Immunity. 20:769–783. https ://doi
.org /10 .1016 /j .immuni .2004 .05 .007
Yoshida, M., K. Kobayashi, T.T. Kuo, L. Bry, J.N. Glickman, S.M. Claypool, A.
Kaser, T. Nagaishi, D.E. Higgins, E. Mizoguchi, et al. 2006. Neonatal Fc
receptor for IgG regulates mucosal immune responses to luminal bacteria.
J. Clin. Invest. 116:2142–2151. https ://doi .org /10 .1172 /JCI27821
Zeiger, R.S., S. Heller, M.H. Mellon, A.B. Forsythe, R.D. O’Connor, R.N.
Hamburger, and M. Schatz. 1989. Eect of combined maternal and
infant food-allergen avoidance on development of atopy in early infancy:
a randomized study. J. Allergy Clin. Immunol. 84:72–89. https ://doi .org
/10 .1016 /0091 -6749(89)90181 -4
Zhu, X., G. Meng, B.L. Dickinson, X. Li, E. Mizoguchi, L. Miao, Y. Wang,
C. Robert, B. Wu, P.D. Smith, et al. 2001. MHC class I-related neonatal
Fc receptor for IgG is functionally expressed in monocytes, intestinal
macrophages, and dendr itic cells. J. Immunol. 166:3266–3276. https ://doi
.org /10 .4049 /jimmunol .166 .5 .3266
... 24,87 Antibodies to both airborne and food allergens have been detected in human milk. 81,88,89 Maternal allergen-specific IgG can be detected in children's serum up to 6 months of age, and the specificity to the allergen in plasma, breast milk and cord blood is quite similar. 23 It is noteworthy that In addition to human breast milk, allergen-specific IgG (bIgG) has been detected in cow's milk. ...
... In addition to possible immune regulation induced by the sole presence of maternal IgG, maternally derived immune complexes made of allergen bound to IgG may also be critical for regulation of long-term allergy susceptibility. Allergen-IgG immune complexes have been detected in cord blood91,92 and human milk.89,92 There is strong evidence from rodent experiments that allergen-IgG immune complexes in breast milk are very potent in eliciting an immune response F I G U R E 3 Maternal immunoglobulin-mediated imprinting of allergic responses in the offspring. ...
... Maternal secretary IgA (orange) are also found in human breast milk and might decrease allergic sensitization by controlling allergen transfer across offspring gut. Evidence in mice also suggests they might control the expansion of Tregs in offspring prolonged tolerance to OVA in offspring subsequently leading to respiratory and food allergy prevention.22,89 This appeared to result from a protected transport of OVA across the gut barrier and an enhanced presentation by dendritic cells, both depending on the use of the neonatal Fc Receptor (FcRn).A recent report analysed the influence of maternal immune status on the induction of protection against cow milk allergic sensitization upon β-lactoglobulin (β-LG) transfer through breast milk.Using two different protocols for maternal immunization, the study showed that the transfer of the antigen without antibody did not lead to protection and that levels of antibodies in breast milk positively correlated with the inhibition of allergic sensitization in offspring.93 ...
... In the study of Yamamoto et al. (37) allergic diarrhea was detected in 59.7% of mice breastfed by OVA-exposed non-sensitized mothers, in 24.6% breastfed by OVA-exposed sensitized mothers, and in 97.1% breastfed by OVA-non-sensitized and OVA-unexposed mothers. This study showed that prior sensitization of mice in conjunction with the consumption of the allergen during lactation (both sensitized and exposed mothers) provided the most potent and long-lasting protection against sensitization to this antigen in mice (38). ...
... In experimental studies, both free allergens and specific antigen immunoglobulins were found in breast milk depending on the immune status of the mother (36,38). Antigen-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) were found in the breast milk of sensitized mothers and formed immune complexes with antigens (39,40). ...
... OVA-specific IgG was found at significantly higher levels in milk from allergic mothers (37,41). The large excess of OVA-specific immune complexes compared to antigen levels (100 µg/ml compared to 100 ng/ml) (37,38) was found to be immunosuppressive (42). Antigens bound in IgA were also detected in human milk (39); however, in animal studies, IgA was not necessary for tolerance induction (29). ...
Article
Full-text available
Food allergy is a common health problem in childhood since its prevalence was estimated to range from 6. 5 to 24.6% in European countries. Recently, a lot of research has focused on the impact of breastfeeding on oral tolerance induction. Since it was found that breast milk contains immunologically active food antigens, it would be very helpful to clarify the factors of antigen shedding that promotes oral tolerance. This narrative review aimed to summarize the latest evidence from experimental and human studies regarding allergen characteristics in human milk that may influence oral tolerance induction. A literature search in PubMed, MEDLINE, and Google Scholar was conducted. The diet of the mother was found to have a direct impact on allergen amount in the breastmilk, while antigens had different kinetics in human milk between women and depending on the antigen. The mode of antigen consumption, such as the cooking of an antigen, may also affect the allergenicity of the antigen in human milk. The dose of the antigen in human milk is in the range of nanograms per milliliter; however, it was found to have a tolerogenic effect. Furthermore, the presence of antigen-specific immunoglobulins, forming immune complexes with antigens, was found more tolerogenic compared to free allergens in experimental studies, and this is related to the immune status of the mother. While examining available data, this review highlights gaps in knowledge regarding allergen characteristics that may influence oral tolerance.
... IgG с этими рецепторами стимулировало формирование оральной толерантности у потомства и предотвращало развитие IgE-опосредованной анафилаксии за счет индукции Tregs [10]. ...
... Также было установлено, что поддержание толерантности к белкам коровьего молока коррелировало с высоким уровнем соответствующих специфических IgG [9]. Интересные данные о роли IgG в формировании оральной толерантности у здорового потомства были добыты в экспериментальных исследованиях [10]. Результаты, полученные в эксперименте на животных, показали формирование оральной толерантности у потомства с участием неонатального Fc-фрагмента (FcRn) -рецептора Fc-фрагмента IgG, который экспрессируется дендритными клетками. ...
Article
Objective: Study specific Igg4 antibodies to milk proteins indexes in healthy babies living in different Russian megalopolises. Methods: The complex research of the specific Igg4 antibodies to milk proteins during cohort study of 259 healthy babies of the first year of life. Children lived in five Russian cities: 60 children in Moscow, 50 newborns – in Saint Petersburg, 55 children came from Kazan, 43 children lived in Khabarovsk and 51 – in Vladivostok. Non-competitive enzyme-linked immunosorbent assay was used to quantify specific Igg4 antibodies to cow milk proteins (CMP), beta-lactoglobulin (β-LG), alpha-lactalbumin (α-LA), casein and goat's milk protein (GM) in coprofiltrates Results: The highest frequency of the high Igg4 was discovered to CMP and goats’ milk was observed among children from Saint Petersburg during comparative assessment of the frequency of defining Igg4 to milk proteins in healthy newborns aged 2.5 months living in Moscow and Saint-Petersburg. The highest frequency of Igg4 increased rates to milk proteins among newborns from Kazan, Khabarovsk and Vladivostok was diagnosed during first three months of life on breastfeeding without any clinical symptoms of food intolerance. With age decrease of the frequency of specific Igg4 to milk proteins were observed among all babies from above-mentioned cities. By 8 month of life it made isolated cases. Conclusions: High frequency of increased Igg4 to milk proteins among 2 months old babies on breastfeeding was observed in the cities of Central and Far Eastern districts of Russian Federation. In this regard it can be supposed that Igg4s were got from mothers in the prenatal period and after birth through breastfeed. The presence of high frequency of the increased indexes of specific Igg4 to milk proteins probably was related to mothers’ nutrition habits during pregnancy and lactation periods.
... Whereas it is clear that the active transport of IgG across the placenta to the unborn is FcRn-mediated 8,9,18 , transport of other isotypes such as IgA and IgM is generally not considered relevant, most likely passive, as only a small fraction of what is found in maternal sera can be found in cord blood 19 . However, FcRn involvement has been reported for the transfer of tolerance to food allergens from mother to offspring in mice 20 as well as for the transfer of IgE in anti-IgE IgG/IgE ICs in mice 21 and humans 22 . A recent study suggested FcRn-dependent placental transport of IgE from mother to offspring in mice 23 . ...
... ovalbumin (OVA) or food allergens to offspring. Transfer of such protective IgG and IgG-ICs has been reported to occur via placental passage and via the mother milk, respectively, both in a FcRn-dependent manner 20,[37][38][39] . ...
Article
Full-text available
The neonatal Fc receptor (FcRn) is known to mediate placental transfer of IgG from mother to unborn. IgE is widely known for triggering immune responses to environmental antigens. Recent evidence suggests FcRn-mediated transplacental passage of IgE during pregnancy. However, direct interaction of FcRn and IgE was not investigated. Here, we compared binding of human IgE and IgG variants to recombinant soluble human FcRn with β2-microglobulin (sFcRn) in surface plasmon resonance (SPR) at pH 7.4 and pH 6.0. No interaction was found between human IgE and human sFcRn. These results imply that FcRn can only transport IgE indirectly, and thereby possibly transfer allergenic sensitivity from mother to fetus.
... For example, Savilahti et al. found that milk tolerance in allergic children was associated with blood IgG levels [35]. In addition, maternal food-specific IgG may be correlated with the food tolerance of offspring [36]. ...
Article
Full-text available
Background Although the association of food-specific IgG with the development and progression of specific diseases was shown by many studies, it is also present in the population without clinical symptoms. However, the association between food-specific IgG and physical examination outcomes in healthy people has not been studied yet. Methods An asymptomatic physical examination cohort (APEC) was selected according to the inclusion and exclusion criteria, the physical examination data were compared between IgG positive and IgG negative groups, and their odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using multivariable logistic regression. Results The data of 28,292 subjects were included in the analysis. The overall IgG positive rate was up to 52.30%, mostly with mild to moderate IgG positivity. The multivariable Logistic regression showed the prevalence of hypertriglyceridemia, abnormal fasting blood glucose and overweight was lower in the IgG (+) positive group (OR 0.87, 95% CI 0.83–0.92; OR 0.93, 95% CI 0.87–0.99; OR 0.92, 95% CI 0.87–0.96) but there was a higher prevalence of thyroid disease (OR 1.09, 95% CI 1.04–1.15). Conclusion Food-specific IgG positivity was widespread in the APEC and was associated with lower prevalence of hypertriglyceridemia, abnormal fasting blood glucose and overweight. The underlying physiological mechanism merits further study.
... 55,58,59 Differences in IgG glycosylation can also alter affinity for activating vs inhibitory FcγRs 60-63 ; for example, defucosylation increases the binding affinity of IgG for activating FcγRIIIA (but not FcγRIIB) 10-50 fold. 64 IgG functions in the intestine in homeostasis include protection against infectious challenge [65][66][67][68] and allergic intolerance, 69 neonatal immune development 53,70 and F I G U R E 2 IgG and IgA cell profiles in the colon: The microbial load of the colon is known to increase from proximal to distal in both mice and man. Memory B cells predominate in the proximal colon, with more plasma cells of both the IgA and IgG variety in the distal colon. ...
Article
Full-text available
The gastrointestinal tract is colonised by trillions of commensal microorganisms that collectively form the microbiome and make essential contributions to organism homeostasis. The intestinal immune system must tolerate these beneficial commensals, whilst preventing pathogenic organisms from systemic spread. Humoral immunity plays a key role in this process, with large quantities of immunoglobulin (Ig)A secreted into the lumen on a daily basis, regulating the microbiome, and preventing bacteria from encroaching on the epithelium. However, there is an increasing appreciation of the role of IgG antibodies in intestinal immunity, including beneficial effects in neonatal immune development, pathogen and tumour resistance, but also of pathological effects in driving chronic inflammation in inflammatory bowel disease (IBD). These antibody isotypes differ in effector function, with IgG exhibiting more pro-inflammatory capabilities compared with IgA. Therefore, the process that leads to the generation of different antibody isotypes, class-switch recombination (CSR), requires careful regulation and is orchestrated by the immunological cues generated by the prevalent local challenge. In general, an initiating signal such as CD40 ligation on B cells leads to the induction of activation-induced cytidine deaminase (AID), but a second cytokine-mediated signal determines which Ig heavy chain is expressed. Whilst the cytokines driving intestinal IgA responses are well-studied, there is less clarity on how IgG responses are generated in the intestine, and how these cues might become dysfunctional in IBD. Here we review the key mechanisms regulating class-switching to IgA versus IgG in the intestine, processes that could be therapeutically manipulated in infection and IBD.
... Breast milk plays a fundamental role in the maturation of the immune system since it supplies components that may be absent or immature, such as IgA that is absent, therefore the only source is breast milk, and others such as IgG that has been identified that by being associated with food allergens improves their tolerance, reinforcing that the introduction of allergens together with breast milk would be a protective factor against FA [26]. ...
Article
Full-text available
The prevalence of food allergy has increased in recent years, especially among the pediatric population. Differences in the gut microbiota composition between children with FA and healthy children have brought this topic into the spotlight as a possible explanation for the increase in FA. The gut microbiota characteristics are acquired through environmental interactions starting early in life, such as type of delivery during birth and breastfeeding. The microbiota features may be shaped by a plethora of immunomodulatory mechanisms, including a predominant role of Tregs and the transcription factor FOXP3. Additionally, a pivotal role has been given to vitamin A and butyrate, the main anti-inflammatory metabolite. These observations have led to the study and development of therapies oriented to modifying the microbiota and metabolite profiles, such as the use of pre- and probiotics and the determination of their capacity to induce tolerance to allergens that are relevant to FA. To date, evidence supporting these approaches in humans is scarce and inconclusive. Larger cohorts and dose-titration studies are mandatory to evaluate whether the observed changes in gut microbiota composition reflect medical recovery and increased tolerance in pediatric patients with FA. In this article, we discuss the establishment of the microbiota, the immunological mechanisms that regulate the microbiota of children with food allergies, and the evidence in research focused on its regulation as a means to achieve tolerance to food allergens.
Article
Full-text available
The prevalence of allergic diseases is on the rise, yet the environmental factors that contribute to this increase are still being elucidated. Laundry detergent (LD) that contains cytotoxic ingredients including microbial enzymes continuously comes into contact with the skin starting in infancy. An impaired skin barrier has been suggested as a route of allergic sensitization. We hypothesized that exposure of skin to LD damages the skin barrier resulting in systemic sensitization to allergens that enter through the impaired skin barrier. Mouse skin samples exposed in vitro to microbial proteases or LD exhibited physical damage, which was more pronounced in neonatal skin as compared to adult skin. Exposure of the skin to microbial proteases in vitro resulted in an increase in the levels of interleukin (IL)-33 and thymic stromal lymphopoietin (TSLP). BALB/c wild type mice epicutaneously exposed to LD and ovalbumin (OVA) showed an increase in levels of transepidermal water loss, serum OVA-specific immunoglobulin (Ig) G1 and IgE antibodies, and a local increase of Il33 , Tslp , Il4 and Il13 compared with LD or OVA alone. Following intranasal challenge with OVA, mice epicutaneously exposed to LD showed an increase in allergen-induced esophageal eosinophilia compared with LD or OVA alone. Collectively, these results suggest that LD may be an important factor that impairs the skin barrier and leads to allergen sensitization in early life, and therefore may have a role in the increase in allergic disease.
Article
In the gut, secretory immunoglobulin A is the predominant humoral response against commensals, although healthy hosts also produce microbiota‐specific IgG antibodies. During intestinal inflammation, the content of IgG in the lumen increases along with the proportion of commensal bacteria coated with this antibody, suggesting signaling through the IgG‐CD64 axis in the pathogenesis of inflammatory bowel diseases. In this work, we evaluated day by day the frequency of fecal bacteria coated with IgA and IgG during the development of DSS colitis. We studied the phenotype and phagocytic activity of F4/80+CD64+ colonic macrophages, as well as the production of cytokines and nitric oxide by lamina propria or bone marrow‐derived macrophages after stimulation with IgA+, IgG+ and IgA+IgG+ bacteria. We found that the percentage of fecal IgA+IgG+ double‐coated bacteria increased rapidly during DSS colitis. Also, analysis of the luminal content of mice with colitis showed a markedly superior ability to coat fresh bacteria. IgA+IgG+ bacteria were the most potent stimulus for phagocytic activity involving CD64 and Dectin‐1 receptors. IgA+IgG+ bacteria observed during the development of DSS colitis could represent a new marker to monitor permeability and inflammatory progression. The interaction of IgA+IgG+ bacteria with CD64+F4/80+ macrophages could be part of the complex cascade of events in colitis. Interestingly, after stimulation, CD64+ colonic macrophages showed features similar to those of restorative macrophages that are relevant for tissue repair and healing.
Article
Full-text available
Food allergies and other immune-mediated diseases have become serious health concerns amongst infants and children in developed and developing countries. The absence of available cures limits disease management to allergen avoidance and symptomatic treatments. Research has suggested that the presence of maternal food allergies may expose the offspring to genetic predisposition, making them more susceptible to allergen sensitization. The following review has focused on epidemiologic studies regarding maternal influences of proneness to develop food allergy in offspring. The search strategy was “food allergy OR maternal effects OR offspring OR prevention”. A systematically search from PubMed/MEDLINE, Science Direct and Google Scholar was conducted. Specifically, it discussed the effects of maternal immunity, microbiota, breastfeeding, genotype and allergy exposure on the development of food allergy in offspring. In addition, several commonly utilized prenatal and postpartum strategies to reduce food allergy proneness were presented, including early diagnosis of high-risk infants and various dietary interventions.
Article
Full-text available
Background: Cutaneous exposure to food allergens predisposes to food allergy, which is commonly associated with atopic dermatitis (AD). Levels of the epithelial cytokine IL-33 are increased in skin lesions and serum of patients with AD. Mast cells (MCs) play a critical role in food-induced anaphylaxis and express the IL-33 receptor ST2. The role of IL-33 in patients with MC-dependent food anaphylaxis is unknown. Objective: We sought to determine the role and mechanism of action of IL-33 in patients with food-induced anaphylaxis in a model of IgE-dependent food anaphylaxis elicited by oral challenge of epicutaneously sensitized mice. Methods: Wild-type, ST2-deficient, and MC-deficient Kit(W-sh/W-sh) mice were epicutaneously sensitized with ovalbumin (OVA) and then challenged orally with OVA. Body temperature was measured by means of telemetry, Il33 mRNA by means of quantitative PCR, and IL-33, OVA-specific IgE, and mouse mast cell protease 1 by means of ELISA. Bone marrow-derived mast cell (BMMC) degranulation was assessed by using flow cytometry. Results: Il33 mRNA expression was upregulated in tape-stripped mouse skin and scratched human skin. Tape stripping caused local and systemic IL-33 release in mice. ST2 deficiency, as well as ST2 blockade before oral challenge, significantly reduced the severity of oral anaphylaxis without affecting the systemic TH2 response to the allergen. Oral anaphylaxis was abrogated in Kit(W-sh/W-sh) mice and restored by means of reconstitution with wild-type but not ST2-deficient BMMCs. IL-33 significantly enhanced IgE-mediated degranulation of BMMCs in vitro. Conclusion: IL-33 is released after mechanical skin injury, enhances IgE-mediated MC degranulation, and promotes oral anaphylaxis after epicutaneous sensitization by targeting MCs. IL-33 neutralization might be useful in treating food-induced anaphylaxis in patients with AD.
Article
Full-text available
Background The age at which allergenic foods should be introduced into the diet of breast-fed infants is uncertain. We evaluated whether the early introduction of allergenic foods in the diet of breast-fed infants would protect against the development of food allergy. Methods We recruited, from the general population, 1303 exclusively breast-fed infants who were 3 months of age and randomly assigned them to the early introduction of six allergenic foods (peanut, cooked egg, cow’s milk, sesame, whitefish, and wheat; early-introduction group) or to the current practice recommended in the United Kingdom of exclusive breast-feeding to approximately 6 months of age (standard-introduction group). The primary outcome was food allergy to one or more of the six foods between 1 year and 3 years of age. Results In the intention-to-treat analysis, food allergy to one or more of the six intervention foods developed in 7.1% of the participants in the standard-introduction group (42 of 595 participants) and in 5.6% of those in the early-introduction group (32 of 567) (P=0.32). In the per-protocol analysis, the prevalence of any food allergy was significantly lower in the early-introduction group than in the standard-introduction group (2.4% vs. 7.3%, P=0.01), as was the prevalence of peanut allergy (0% vs. 2.5%, P=0.003) and egg allergy (1.4% vs. 5.5%, P=0.009); there were no significant effects with respect to milk, sesame, fish, or wheat. The consumption of 2 g per week of peanut or egg-white protein was associated with a significantly lower prevalence of these respective allergies than was less consumption. The early introduction of all six foods was not easily achieved but was safe. Conclusions The trial did not show the efficacy of early introduction of allergenic foods in an intention-to-treat analysis. Further analysis raised the question of whether the prevention of food allergy by means of early introduction of multiple allergenic foods was dose-dependent. (Funded by the Food Standards Agency and others; EAT Current Controlled Trials number, ISRCTN14254740.)
Article
Full-text available
The neonatal FcR (FcRn) belongs to the extensive and functionally divergent family of MHC molecules. Contrary to classical MHC family members, FcRn possesses little diversity and is unable to present Ags. Instead, through its capacity to bind IgG and albumin with high affinity at low pH, it regulates the serum half-lives of both of these proteins. In addition, FcRn plays an important role in immunity at mucosal and systemic sites through its ability to affect the lifespan of IgG, as well as its participation in innate and adaptive immune responses. Although the details of its biology are still emerging, the ability of FcRn to rescue albumin and IgG from early degradation represents an attractive approach to alter the plasma half-life of pharmaceuticals. We review some of the most novel aspects of FcRn biology, immune as well as nonimmune, and provide some examples of FcRn-based therapies. Copyright © 2015 by The American Association of Immunologists, Inc.
Article
Full-text available
Oral immunotherapy has had limited success in establishing tolerance in food allergy, reflecting failure to elicit an effective regulatory T (Treg) cell response. We show that disease-susceptible (Il4ra(F709)) mice with enhanced interleukin-4 receptor (IL-4R) signaling exhibited STAT6-dependent impaired generation and function of mucosal allergen-specific Treg cells. This failure was associated with the acquisition by Treg cells of a T helper 2 (Th2)-cell-like phenotype, also found in peripheral-blood allergen-specific Treg cells of food-allergic children. Selective augmentation of IL-4R signaling in Treg cells induced their reprogramming into Th2-like cells and disease susceptibility, whereas Treg-cell-lineage-specific deletion of Il4 and Il13 was protective. IL-4R signaling impaired the capacity of Treg cells to suppress mast cell activation and expansion, which in turn drove Th2 cell reprogramming of Treg cells. Interruption of Th2 cell reprogramming of Treg cells might thus provide candidate therapeutic strategies in food allergy. Copyright © 2015 Elsevier Inc. All rights reserved.
Article
Full-text available
Immunoglobulin (Ig)E-associated food allergy affects approximately 3% of the population and has severe effects on the daily life of patients—manifestations occur not only in the gastrointestinal tract but affect also other organ systems. Birth cohort studies have demonstrated that allergic sensitization to food allergens develops early in childhood. Mechanisms of pathogenesis include cross-linking of mast cell- and basophil-bound IgE and immediate release of inflammatory mediators, as well as late-phase and chronic allergic inflammation, due to T cell, basophil, and eosinophil activation. Researchers have begun to characterize the molecular features of food allergens and developed chip-based assays for multiple allergens. These have provided information about cross-reactivity among different sources of food allergens, identified disease-causing food allergens, and helped us to estimate the severity and types of allergic reactions in patients. Importantly, learning about the structure of disease-causing food allergens has allowed researchers to engineer synthetic and recombinant vaccines.
Article
Background: Food-allergic subjects produce high-titer IgE antibodies that bind to mast cells via FcεRI and trigger immediate hypersensitivity reactions upon antigen encounter. Food-specific IgG antibodies arise in the setting of naturally resolving food allergy and accompany the acquisition of food allergen unresponsiveness in oral immunotherapy (OIT). Objective: In this study, we sought to delineate the effects of IgG and its inhibitory Fc receptor, FcγRIIb, on both de novo allergen sensitization in naïve animals and on established immune responses in the setting of pre-existing food allergy. Methods: Allergen-specific IgG was administered to mice undergoing sensitization and desensitization to the model food allergen, ovalbumin (OVA). Cellular and molecular mechanisms were interrogated using mast cell- and FcγRIIb-deficient mice. The requirement for FcγRII in IgG-mediated inhibition of human mast cells was investigated using a neutralizing antibody. Results: Administration of specific IgG to food allergy-prone IL4raF709 mice during initial food exposure prevented the development of IgE antibodies, T helper (Th) 2 responses, and anaphylactic responses upon challenge. When given as an adjunct to oral desensitization in mice with established IgE-mediated hypersensitivity, IgG facilitated tolerance restoration, favoring the expansion of Foxp3(+) regulatory T cells (Treg) along with suppression of existing Th2 and IgE responses. IgG and FcγRIIb suppresses the adaptive allergic responses via effects on mast cell function. Conclusion: These findings suggest that allergen-specific IgG antibodies can act to induce and sustain immunological tolerance to foods.
Article
Background: Oral tolerance induction in early life is a promising approach for food allergy prevention. Its success requires the identification of factors necessary for its persistence. Objectives: We aimed to assess in mice duration of allergy prevention by breastfeeding-induced oral tolerance and whether oral TGF-β supplementation after weaning would prolong it. Methods: We quantified ovalbumin (OVA) and OVA-specific immunoglobulin levels by ELISA in milk from the EDEN birth cohort. As OVA-specific Ig was found in all samples, we assessed whether OVA-immunized mice exposed to OVA during lactation could prevent allergic diarrhoea in their 6- and 13-week-old progeny. In some experiments, a TGF-β-enriched formula was given after weaning. Results: At 6 weeks, only 13% and 34% of mice breastfed by OVA-exposed mothers exhibited diarrhoea after six and seven OVA challenges vs. 44% and 72% in mice breastfed by naïve mothers (P = 0.02 and 0.01). Protection was associated with decreased levels of MMCP1 and OVA-specific IgE (P < 0.0001). At 13 weeks, although OVA-specific IgE remained low (P = 0.001), diarrhoea occurrence increased to 32% and 46% after six and seven OVA challenges in mice breastfed by OVA-exposed mothers. MMCP1 levels were not significantly inhibited. Supplementation with TGF-β after weaning induced a strong protection in 13-week-old mice breastfed by OVA-exposed mothers compared with mice breastfed by naive mothers (0%, 13% and 32% of diarrhoea at the fifth, sixth and seventh challenges vs. 17, 42 and 78%; P = 0.05, 0.0043 and 0.0017). MMCP1 levels decreased by half compared with control mice (P = 0.02). Prolonged protection was only observed in mice rendered tolerant by breastfeeding and was associated with an improved gut barrier. Conclusions: In mice, prevention of food allergy by breastfeeding-induced tolerance is of limited duration. Nutritional intervention by TGF-β supplementation after weaning could prolong beneficial effects of breast milk on food allergy prevention.
Article
Background: Studies of a limited number of allergens suggested that nonsensitized children produce IgG responses mainly to foodborne allergens, whereas IgE-sensitized children also produce strong IgG responses to the respective airborne molecules. Objective: We sought to systematically test the hypothesis that both the route of exposure and IgE sensitization affect IgG responses to a broad array of allergenic molecules in early childhood. Methods: We examined sera of 148 children participating in the Multicentre Allergy Study, a birth cohort born in 1990. IgG to 91 molecules of 42 sources were tested with the ImmunoCAP Solid-Phase Allergen Chip (ISAC; TFS, Uppsala, Sweden). IgE sensitization at age 2 and 7 years was defined by IgE levels of 0.35 kUA/L or greater to 1 or more of 8 or 9 extracts from common allergenic sources, respectively. Results: The prevalence and geometric mean levels of IgG to allergenic molecules in nonsensitized children were lower at age 2 years than in IgE-sensitized children, and they were extremely heterogeneous: highest for animal food (87% ± 13%; 61 ISAC Standardized Units [ISU], [95% CI, 52.5-71.5 ISU]), intermediate for vegetable food (48% ± 27%; 13 ISU [95% CI, 11.2-16.1 ISU]), and lowest for airborne allergens (24% ± 20%; 3 ISU [95% CI, 2.4-3.4 ISU]; P for trend < .001 [for percentages], P for trend < .001 [for levels]). IgG4 antibodies were infrequent (<5%) and contributed poorly (<3%) to overall IgG antibody levels. IgG responses at age 2 years were slightly more frequent and stronger among children with than in those without IgE sensitization at age 7 years. Conclusion: The children's repertoire of IgG antibodies at 2 years of age to a broad array of animal foodborne, vegetable foodborne, and airborne allergenic molecules is profoundly dependent on the route of allergen exposure and the child's IgE sensitization status and only marginally involves the IgG4 isotype.
Article
Background: Eosinophilic esophagitis (EoE) is an allergic inflammatory disorder characterized by accumulation of eosinophils in the esophagus. EoE often coexists with atopic dermatitis, a chronic inflammatory skin disease. The impaired skin barrier in patients with atopic dermatitis has been suggested as an entry point for allergic sensitization that triggers development of EoE. Objective: We sought to define the mechanisms whereby epicutaneous sensitization through a disrupted skin barrier induces development of EoE. Methods: To elicit experimental EoE, mice were epicutaneously sensitized with ovalbumin (OVA), followed by intranasal OVA challenge. Levels of esophageal mRNA for TH2 cytokines and the IL-33 receptor Il1rl1 (St2) were measured by using quantitative PCR. Esophageal eosinophil accumulation was assessed by using flow cytometry and hematoxylin and eosin staining. In vivo basophil depletion was achieved with diphtheria toxin treatment of Mcpt8(DTR) mice, and animals were repopulated with bone marrow basophils. mRNA analysis of esophageal biopsy specimens from patients with EoE was used to validate our findings in human subjects. Results: Epicutaneous sensitization and intranasal challenge of wild-type mice resulted in accumulation of eosinophils and upregulation of TH2 cytokines and St2 in the esophagus. Disruption of the IL-33-ST2 axis or depletion of basophils reduced these features. Expression of ST2 on basophils was required to accumulate in the esophagus and transfer experimental EoE. Expression of IL1RL1/ST2 mRNA was increased in esophageal biopsy specimens from patients with EoE. Topical OVA application on unstripped skin induced experimental EoE in filaggrin-deficient flaky tail (ft/ft) mice but not in wild-type control or ft/ft.St2(-/-) mice. Conclusion: Epicutaneous allergic sensitization promotes EoE, and this is critically mediated through the IL-33-ST2-basophil axis.