FcR-Bearing Myeloid Cells Are Responsible for Triggering
Murine Lupus Nephritis1
Amy Bergtold,* Anamika Gavhane,†Vivette D’Agati,‡Michael Madaio,§and Raphael Clynes2†
Lupus glomerulonephritis is initiated by deposition of IgG-containing immune complexes in renal glomeruli. FcR engagement by
immune complexes (IC) is crucial to disease development as uncoupling this pathway in FcR??/?abrogates inflammatory re-
sponses in (NZB ? NZW)F1mice. To define the roles of FcR-bearing hemopoietic cells and of kidney resident mesangial cells in
pathogenesis, (NZB ? NZW)F1bone marrow chimeras were generated. Nephritis developed in (NZB ? NZW)F1mice expressing
activating FcRs in hemopoietic cells. Conversely, recipients of FcR??/?bone marrow were protected from disease development
despite persistent expression of FcR? in mesangial cell populations. Thus, activating FcRs on circulating hemopoietic cells, rather
than on mesangial cells, are required for IC-mediated pathogenesis in (NZB ? NZW)F1. Transgenic FcR??/?mice expressing
FcR? limited to the CD11b?monocyte/macrophage compartment developed glomerulonephritis in the anti-glomerular basement
disease model, whereas nontransgenic FcR??/?mice were completely protected. Thus, direct activation of circulating FcR-bearing
myeloid cells, including monocytes/macrophages, by glomerular IC deposits is sufficient to initiate inflammatory responses. The
Journal of Immunology, 2006, 177: 7287–7295.
tis. Studies of acute murine models of Ab-mediated inflammation
in the skin (1–4), joints (5–12), lungs (13), kidneys (14–19), and
peritoneum (20, 21) in gene-deficient mice permit the general con-
clusion that the coordinate expression of activating and inhibitory
FcRs on effector cells regulates inflammatory responses. Comple-
ment components including C5a contribute directly as chemoat-
tractants and as inducers of preferential up-regulation of activating
FcRs on effector cells (20, 22–24).
The initial events following IC deposition in the tissues include
the local activation of complement and the triggering of tissue-
resident cells though their Fc and complement receptors. The re-
sultant collective action of locally produced chemokines, cyto-
kines, and small molecule mediators of inflammation activates
endothelial cells and promotes the adhesion and diapedesis of ac-
tivated bloodborne effectors, including monocytes and neutrophils,
into the tissue. In this scenario, the recruitment of circulating cel-
lular effectors is expected to occur as a consequence of local ac-
tivation of resident tissue cells. The importance of resident cells
including tissue macrophages and mast cells in the initiation of the
mmune complex (IC)3deposition in tissue contributes to
many autoimmune disease states including systemic vascu-
litis, arthritis, blistering skin diseases, and glomerulonephri-
inflammatory cascade and subsequent recruitment of circulating
neutrophils has been demonstrated in the joints (25–27) and in
Arthus reactions in the lungs (13, 22, 28), peritoneum (21, 29, 30),
and skin (3).
In the kidney, the relevant resident cell that would be expected
to initiate the inflammatory response to ICs deposited in glomeruli
is the mesangial cell (MC). MC activation contributes directly to
glomerular pathogenesis through proliferation and collagen depo-
sition and indirectly through the production of the inflammatory
mediators (31, 32) cytokines and chemokines (31, 33). Indeed,
FcRs are expressed on cultured rodent and human MC (34–36),
and Fc?R cross-linking on cultured MC induces matrix deposition
(34) and the production of inflammatory mediators including che-
mokines (37, 38) and cytokines (39). Numerous studies have im-
plicated Fc?R cross-linking on MC as a proximal and key step in
IC-mediated nephritis, yet few studies have directly demonstrated
mesangial expression of Fc?R in vivo. Low-level expression of the
inhibitory Fc?RIIB on glomerular cells was detectable by immu-
nohistochemistry (17), but other studies have failed to detect Fc?R
at the RNA level (40). FcR??/?mice are protected from the de-
velopment of nephritis despite IC mesangial deposition (18, 19).
However, a requisite inflammatory role of FcRs on MC in vivo
Recent work in the anti-glomerular basement membrane (anti-
GBM) model suggests instead that circulating hemopoietic cells
directly engage immune deposits in the mesangium, initiating the
inflammatory response without prior recruitment by FcR-engaged
MC. Transferred wild-type (WT) neutrophils become activated in
FcR??/?hosts bearing IC mesangial deposits, arguing that acute
injury can be initiated by FcR cross-linking-circulating neutrophils
(41). In bone marrow (BM) chimeras (42) using FcR??/?and
FcR??/?donors and recipients, anti-GBM nephritis required FcR-
bearing cells in the hemopoietic compartment, suggesting that MC
FcR engagement is not necessary for the induction of the IC-me-
diated inflammatory responses (42). Although these short-term
acute models provide important mechanistic insights, the sponta-
neous nephritis model in (NZB ? NZW)F1mice most closely
approximates pathogenetic mechanisms mediating human lupus
nephritis. We have addressed the role of FcR? in intrinsic renal
*Integrated Program in Cellular, Molecular, and Biophysical Studies,†Department of
Microbiology and Medicine,‡Department of Pathology, Columbia University, Col-
lege of Physicians and Surgeons, New York, NY 10032; and§Department of Med-
icine, University of Pennsylvania, School of Medicine, Philadelphia, PA 19104
Received for publication December 20, 2005. Accepted for publication September
The costs of publication of this article were defrayed in part by the payment of page
charges. This article must therefore be hereby marked advertisement in accordance
with 18 U.S.C. Section 1734 solely to indicate this fact.
1This work was supported by the Immunology Training Program (T32 AI 07525 (to
A.B.), the National Institutes of Health/National Institute of Allergy and Infectious
Diseases RO3AR45764, and by an Investigator Award of the Arthritis Foundation
2Address correspondence and reprint requests to Dr. Raphael Clynes, Columbia Uni-
versity, College of Physicians and Surgeons, P & S Building, Room 8-510, 630 West
168th Street, New York, NY 10032. E-mail address: firstname.lastname@example.org
3Abbreviations used in this paper: IC, immune complex; MC, mesangial cell; GBM,
glomerular basement membrane; WT, wild type; BM, bone marrow; PAS, periodic
acid-Schiff; SLE, systemic lupus erythematosus.
The Journal of Immunology
Copyright © 2006 by The American Association of Immunologists, Inc.0022-1767/06/$02.00
cells or hemopoietic cells in the spontaneous NZB/NZW lupus
nephritis model and find that mesangial FcR expression is not re-
quired for disease development. Furthermore, we have partially
reconstituted anti-GBM nephritis in FcR??/?by transgenic ex-
pression of FcR? in the monocyte/macrophage compartment, im-
plicating direct activation of this FcR-bearing cellular subset in the
initiation of the inflammatory phase of IC-mediated nephritis.
Thus, direct activation of FcR-bearing monocyte/macrophages is
sufficient to induce inflammatory responses in response to glomer-
ular IC deposition.
Materials and Methods
(NZB ? NZW)F1FcR??/?mice were generated from an intercross of
NZB FcR??/?male and NZW FcR??/?female mice (18). To generate
BM chimeras, 10 ? 106BM cells obtained from 3-wk-old (NZB ?
NZW)F1FcR??/?and FcR??/?mice (The Jackson Laboratory) were in-
jected i.v. into the tail vein of lethally irradiated recipients (1000 rad ? 1
dose). Chimeric mice were given oral ciprofloxacin in the water ad libitum
for 14 days after reconstitution and followed for the development of pro-
teinuria weekly for 9 mo. Proteinuria was read using Urostix for the NZB/
NZW mice and scored positive if 2? measurements (?250 mg/dl) were
recorded for two successive readings. A subset of mice was sacrificed at 6
mo for histopathological analysis of the kidney. These studies were re-
viewed and approved by the Institution Animal Care and Use Committee
of Columbia University.
CD11b-? Tg?mice were generated after injection of oocytes obtained
from FcR??/?mice. The transgenic construct was generated by insertion
of the murine FcR? cDNA (550-bp fragment) as an EcoRI fragment (43)
into pB203 (a gift from Dr. D. G. Tenen, Harvard Medical School, Boston,
MA; see Ref 44) containing the 1.7-kb 5?-flanking sequences of the mouse
CD11b promoter and the 3?-flanking region from the human growth hor-
mone gene. A NotI/HindIII fragment (containing 5?-CD11bpromoter-FcR?
cDNA-hGH-3?) was injected into the oocytes and three founder lines har-
boring the transgene were further analyzed for expression. Of these three
founders, only one (line 14) expressed the FcR? chain in peritoneal
Accelerated anti-GBM nephritis
Mice were immunized with 100 ?g of sheep IgG in CFA 3 days before i.v.
injection of 150 ?l of specific sheep anti-mouse GBM sera. Urine was
obtained daily and blood obtained on the day before injection with anti-
GBM sera and then at the time of sacrifice 7 days later. Urine samples were
diluted in PBS and protein quantified by the Bradford method (Bio-Rad)
using an ELISA plate reader at OD570.
Anti-dsDNA and soluble immune complex ELISAs
Diluted serum (1/100) from 6- to 7-mo-old NZB/NZW-??/?and NZB/
NZW-??/?mice were added to ELISA plates coated with C1q (Sigma-
Aldrich) for detection of ICs (45, 46) and to dsDNA-coated plates (United
Biotech) for detection of Abs to chromatin. After washing away unbound
serum, rat anti-mouse IgG (BD Pharmingen) was added. Alkaline phos-
phatase-conjugated AKP polyclonal anti-rat IgG (BD Pharmingen) was
used as secondary Ab. After incubation with p-nitrophenyl phosphate sub-
strate, the samples were read spectrophotometrically at 405 nm with an
ELISA reader (Molecular Devices).
Immunofluorescence and immunohistochemistry
For histological analysis, formalin-fixed sections were stained with H&E or
periodic acid-Schiff (PAS). To detect IC deposition, paraformaldehyde- or
acetone-fixed cryosections were stained with (1/1000 diluted) FITC goat
anti-mouse C3 and IgG (Valeant Pharmaceuticals). To detect FcR?, a poly-
clonal anti-FcR? rabbit IgG (gift from Dr. J. Ravetch, The Rockefeller
University) or rat anti-Mac-1 (clone C71/16; BD Pharmingen) followed by
rabbit anti-rat IgG Alexa594 (Molecular Probes). Biotinylated goat anti-
rabbit IgG, followed by either streptavidin-FITC or streptavidin-HRP was
used for detection. A Nikon Eclipse 600 microscope equipped with a RT
Spot digital camera was used for imaging.
Renal pathological assessment
PAS sections were prepared from WT, FcR??/?, and FcR??/?CD11b-?
Tg?kidneys on day 7 after induction of accelerated glomerulonephritis
(five per group). Slides were examined in a blinded fashion by one of us
(V. d’A.). Severity of the following seven categories of histological activity
were semiquantitatively graded as follows: glomerular fibrinoid necrosis
0–4, endocapillary hypercellularity 0–4, glomerular leukocyte infiltration
0–4, crescents 0–4, tubular degeneration 0–4, casts 0–4, and interstitial
inflammation 0–4.The cumulative pathological score is the sum of all
seven categories and has a possible range of 0–28.
MC and NK culture
Glomeruli were isolated with successive sieving (47). Kidneys were
minced with scissors and tissue fragments were passed through a no. 60
mesh sieve (Fisher Scientific) and then sequentially passed through no. 100
and no. 200 sieves. Glomeruli were digested with 0.1% collagenase type IV
(Sigma-Aldrich) and 0.1% trypsin (Invitrogen Life Technologies) for 30
min at 37°C before plating in 24 wells in DMEM/10% FCS. Cells were
passaged in D-valine-substituted medium to eliminate fibroblasts. After 2
wk in culture, cells exhibited a stellate morphology and were replated.
Immunostains were smooth muscle actin-positive, weakly 2.4G2?and
Mac-1?, confirming their MC origin. RNA was prepared from MCs using
TRIzol and cDNA was generated using the cloned avian myeloblastosis
virus first-strand synthesis kit according to the manufacturer’s protocol
(Invitrogen Life Technologies). Primer sequences for RT-PCR amplifica-
tion (30 cycles) of FcR? were as follows: 5?-CCAGGATGATCTC
AGCCG-3? and 5?-ACAGTAGAGTAGGGTAAG-3?. These primers am-
plify a 137-bp band corresponding to exons 1 and 2 of the ? subunit. The
band is not amplified in genomic DNA due to intervening intronic se-
quences. The housekeeping gene, HPRT, was amplified from cDNA using
the following primer sequences: 5?-AGCTACTGTAATGATCAGTCA
ACG-3? and 5?-AGAGGTCCTTTTCACCAGCA-3?. For assessing MC
chimerism, genomic DNA was subjected to PCR analysis using the fol-
lowing primer sequences: neo, CTCGTGCTTTACGGTATCGCC; ?-1,
TATAGCTGCCTT. Annealing temperature was 62°C. Knockout and WT-
amplified products were 260 and 224 bp, respectively.
Hemopoietic chimerism was assessed in cultured NK cells obtained af-
ter isolation of the adherent cell population from a 14-day culture of nylon
wool nonadherent splenocytes grown in IL-2 (10,000 U/ml). Flow cyto-
metric analysis used anti-NK1.1 PE and 2.4G2-FITC (BD Pharmingen).
Murine NK cells do not express FcRIIb (48) and thus the anti-FcRII/III
mAb (2.4G2) recognizes only FcRIII on these cells.
Western blot analysis of FcR? expression
Protein extracts were obtained from B cells, T cells, NK cells, and neu-
trophils were immunoblotted with polyclonal rabbit anti-mouse FcR?
chain IgG and anti-?-actin Abs. Neutrophils were obtained from thiogly-
colate- elicited peritoneal exudates (4 h after i.p. injection of thioglycolate)
after GR-1?bead selection (Miltenyi Biotec). Adherent peritoneal macro-
phages were obtained from thioglycolate-elicited exudates (72 h after i.p.
injection). B and T cells were obtained from CD43?and CD3?splenocyte
populations, respectively. All cell populations were lysed in TBS buffer
that contained 1% Triton X-100, 2 mM EDTA, and complete mini-protease
Rabbit IgG-opsonized SRBCs were prepared with subagglutinating quan-
tities of rabbit anti-sheep RBC IgG (MP Biomedicals). After washing away
free Ab, IgG-opsonized RBCs were added to adherent macrophages for 1 h
at 37°C. Unphagocytosed RBCs were removed by osmotic lysis, and
phagocytosis plates were fixed with PBS/0.25% glutaraldehyde before mi-
Blood albumin and urea nitrogen measurements
Blood samples were read by the Clinical Chemistry Laboratory of the
Irving Clinical Research Center at Columbia-Presbyterian Hospital.
BM chimeric NZB/NZW mice reveal a requirement for
FcR?-expressing hemopoietic cells for nephritis development
(NZB ? NZW)F1female mice develop a uniformly fatal rapidly
progressive IC nephritis heralded by the serological appearance of
anti-chromatin IgG autoantibodies at 4–6 mo of age. Disease pro-
gression is swift, with a median survival of 180 days. However, in
(NZB ? NZW)F1FcR ??/?female mice, IgG autoantibodies oc-
cur with equivalent titers and are deposited similarly in the kidney,
7288FcR-BEARING MYELOID CELLS TRIGGER LUPUS NEPHRITIS
but induce little subsequent inflammation (18). Disease progres-
sion is markedly attenuated with median survival of ?400 days
with many animals living a normal life span. To distinguish the
role of FcR-bearing hemopoietic cells from FcR-bearing renal cell
in the development of the effector response in (NZB ? NZW)F1
nephritis, BM transplants between FcR??/?and FcR??/?mice
Hemopoietic reconstitution of lethally irradiated recipients was
assessed by immunophenotypic analysis of NK populations from
representative mice 4 mo postreconstitution. NK populations from
WT BM recipients uniformly expressed Fc?RIII, whereas FcR??/?
recipients were Fc?RIII negative, consistent with complete or near-
complete hemopoietic reconstitution by donor marrow (Fig. 1A). Glo-
in FcR??/?3 FcR??/?reciprocal chimeric mice, indicating that in-
trinsic glomerular cells in the kidney, presumably MC, remained
recipient derived (Fig. 1B) 4 mo after transplant. As previously
seen in nontransplanted NZB/NZW, FcR? deficiency has little im-
pact on the development of autoantibodies and their glomerular
deposition when assessed 6 mo after transplant. All experimental
groups developed anti-chromatin
C1q-binding activity (indicative of the presence of circulating ICs
and/or anti-C1q autoantibodies (45, 46)) regardless of the FcR?
genotype status of the host or recipient (Fig. 2, A and B). Circu-
lating ICs were deposited in the glomeruli in a similar fashion as
assessed by immunofluorescence studies demonstrating equivalent
IgG and complement glomerular deposition in all experimental
groups (Fig. 2C).
Although the afferent limb of autoimmunity was intact regard-
less of the FcR? genotype, the efferent response required activat-
ing FcR-expressing hemopoietic cells. Proteinuria occurred in 90–
100% of the NZB/NZW recipients of WT BM regardless of the
host genotype, whereas proteinuria occurred in only 10–20% of
recipients of NZB/NZW FcR??/?marrow (Fig. 3A). Thus, WT
hemopoietic cells can transfer disease susceptibility to FcR??/?
hosts and conversely FcR??/?BM-derived cells limit disease de-
velopment in WT NZB/NZW hosts, indicating that hemopoietic
expression of activating FcRs is both necessary and sufficient for
the development of nephritis.
mopoietic reconstitution whereas intrinsic renal cells remain recipient de-
rived. A, Six- to 8-wk-old irradiated (1000 cGy) NZB/NZW ??/?and ??/?
mice were reconstituted with 5 ? 106BM cells obtained from either NZB/
NZW ??/?or ??/?3-wk-old mice. Hemopoietic reconstitution was as-
sessed by immunophenotyping NK cell populations of mixed chimeras
(??/?3??/?and ??/?3??/?). Murine NK cells express FcRIII as their
sole Fc receptor and thus anti-FcRII/III mAb 2.4G2 binding reflects ex-
pression of the FcR?-dependent FcRIII. NK cells were ?98% donor de-
rived. B, Frozen renal sections of mice in A were stained with a polyclonal
rabbit anti-FcR? IgG and counterstained with hematoxylin. FcR? was de-
tected in ??/?3??/?but not in ??/?3??/?BM chimeras, indicating that
intrinsic renal cells remained predominantly recipient-derived 4 mo after
(NZB ? NZW)F1BM chimeras show complete donor he-
of FcR? status. A and B, Anti-dsDNA IgG and circulating IC detected in 1/100 dilutions of sera from BM chimeric mice 6 mo after transplant.
Anti-chromatin IgG, IgMs, and circulating IC were similar in all groups (ANOVA, p values of 0.404, 0.517, and 0.240, respectively). Notably, however,
??/?3??/?trended toward higher titers than that of ??/?3??/?(in all cases, except for IgG1 antichromatin, data not shown). C, Immunostains of fixed
frozen renal sections using anti-mouse IgG and anti-mouse complement revealed glomerular deposition in both mixed BM chimeras. Representative
examples of five mice per group are shown.
NZB/NZW BM chimeras develop similar levels of anti-chromatin autoantibodies, circulating IC, and glomerular IC deposition regardless
7289The Journal of Immunology
Histological analysis revealed fulminant glomerulonephritis in
recipients of WT BM with glomerular hypertrophy, mesangial and
endocapillary hypercellularity, neutrophilic and monocytic infil-
tration, necrosis, crescent formation, and sclerosis (Fig. 3B). In
contrast, disease protection was seen in ??/?BM recipients with
histological changes limited to mesangial expansion and mild en-
docapillary and mesangial hypercellularity.
These data suggest that FcR expression by resident cells of the
kidney does not critically contribute to the initiation of the effector
response in IC-triggered nephritis. The immunohistochemical analy-
sis of FcR? expression in Fig. 1 was performed on mice 4 mo post-
transplant and before disease onset. To confirm that MC remained
genotypically host derived at 6–9 mo, the time point when proteinuria
became evident, MC were isolated and additional immunostains were
at 6 mo posttransplant, many dual-positive FcR??Mac-1?cells were
present, indicative of infiltrating myeloid lineage cells. In healthy
FcR??/?3FcR??/?chimeric mice sacrificed 9 mo posttransplant,
immunostaining demonstrated persistent glomerular ? expression,
presumably in Mac-1?MC. In an additional experimental approach
to establish the donor vs host FcR? status of MC, MC populations
were enriched from disrupted glomeruli of chimeric mice at 6 mo
posttransplant in nephritic FcR??/?3FcR??/?mice and at 9 mo
from non-nephritic FcR??/?3FcR??/?mice and assessed for the
presence of WT and knockout FcR? alleles by genomic PCR. En-
riched MC populations exhibited typical stellate morphology and
were smooth-muscle actin positive (data not shown). PCR analysis of
genomic DNA of these MC populations (Fig. 3, C, insets, and D) at
6 mo indicated that genotypically these populations continued to in-
clude predominantly host-derived MC. Notably, however, in glomer-
ular cultures obtained from FcR??/?3FcR??/?mice at 9 mo
posttransplant, there was also PCR evidence for donor-derived
contributions consistent with replacement of some MC with BM-
derived precursors, although this was not evident by immunohis-
tochemistry. One possible explanation for the discrepancy between
the immunohistochemical data and the PCR data are that the
measurements were recorded weekly in BM chimeric mice posttransplant. All recipients of FcR??/?BM developed proteinuria by 12 mo posttransplant,
regardless of FcR? genotypic status of the recipient (??/?3??/?(n ? 17); ??/?into ??/?(n ? 10), mean age of onset, respectively, 198 ? 40 days and
186 ? 40 days). Conversely, proteinuria occurred rarely in recipients of FcR??/?BM during the 12-mo observation period (3 of 23 ??/?3??/?mice and
in 1 of 10 ??/?3??/?mice]. Two-sided Fisher’s exact ??/?3??/?vs ??/?3??/?, p ? 2.5 ? 10?8. B, H&E-stained sections demonstrate glomeru-
losclerosis and crescent formation in ??/?3??/?and ??/?3??/?kidneys. Glomerular hypertrophy and end-stage fibrotic changes were consistently found
in this group of mice when proteinuria became evident. Histological changes in ??/?3??/?and ??/?3??/?mice 6 mo posttransplant were minimal and
included mesangial thickening but little sclerosis and minimal increased cellularity. C, ??/?3??/?chimeras: immunofluorescence staining for Mac-1 (red) and
FcR? (green) reveals persistent FcR? expression and lack of infiltrating Mac-1?cells in non-nephritic animals at 9 mo posttransplant. Inset, PCR analysis
of isolated DNA from MC populations isolated from glomeruli reveal persistence of host FcR??alleles. ??/?3??/?chimeras: infiltrating dual-positive
FcR??, Mac-1?cells are seen in nephritic animals at 6 mo posttransplant, consistent with monocyte/macrophage infiltration of glomeruli. Inset, PCR
analysis of MC DNA reveals persistence of the disrupted host-derived FcR? allele in FcR??/?recipients. D, Enriched MC cultures were obtained from
five chimeric mice and two control nontransplanted C57BL/6 ??/?and ??/?mice are shown. ??/?3??/?and ??/?3??/?chimeric mice were sacrificed
at 9 and 6 mo, respectively. The ??/?3??/?MC PCRs indicate a predominance of host-derived MC, whereas by 9 mo PCR evidence for replacement
by donor-derived sources became more evident.
Lupus nephritis requires activating FcR expression in the hemopoietic compartment but not in renal intrinsic MC. A, Urinary protein
7290FcR-BEARING MYELOID CELLS TRIGGER LUPUS NEPHRITIS
enriched MC populations might have included other cells, includ-
ing contaminating leukocytes that were detectable by these sensi-
tive PCR assays. Taken together, these data indicate that FcR ex-
pression of MC is neither necessary nor sufficient to initiate an
inflammatory nephritic response to IC. Rather, inflammation oc-
curs in NZB/NZW as a direct consequence of FcR engagement on
Lineage-specific transgenic reconstitution of FcR? in monocytes/
macrophages partially restores the ability to develop nephritis
To genetically determine the role of myeloid cells by transgenic
manipulation of FcR??/?mice, we turned to the anti-GBM ne-
phritis model in the C57BL/6 FcR??/?background. In previous
studies in the autologous anti-GBM disease model, activating FcRs
expressed on hemopoietic cells were found to be required for dis-
ease development (42). To assess the specific contributions of
FcR-bearing myeloid cells, transgenic mice expressing FcR?
driven by the CD11b promoter (Fig. 4A) were generated in
FcR??/?C57BL/6 mice (CD11b-? Tg?). Three Tg?founder
mice were analyzed for functional expression of FcR? in perito-
neal macrophages. One of theses transgenic founder lines (line 14)
exhibited FcR? expression in peritoneal macrophages, but not in B
cells, T cells, NK cells, or neutrophils (Fig. 4B). Functional ex-
pression in peritoneal macrophages was shown by restored FcR-
mediated phagocytosis in CD11b-? Tg?(Fig. 4C). Lack of ex-
pression of FcR? in MC of CD11b-? Tg?was demonstrated by
RT-PCR analysis of RNA obtained from cultured MC. CD11b-?
Tg?MC did not express detectable FcR? at the RNA level neither
in the resting state nor after stimulation with IC or IFN-? for either
6 h (data not shown) or 24 h (Fig. 4D).
The transgenic CD11b-? Tg?mice provided a unique opportu-
nity to address the singular role of FcR-bearing monocytes/mac-
rophages to the development of nephritis. Mice were immunized
with sheep IgG in CFA 3 days before i.v. administration of specific
sheep anti-GBM sera (Fig. 5). Severe proteinuria, hypoalbumine-
mia, and uremia developed in all WT C57BL/6 mice by day 7
whereas FcR??/?mice, as expected, were completely protected
from disease development (Fig. 5). In contrast, CD11b-? Tg?
mice developed moderate proteinuria and consequent hypoalbu-
minemia. Histopathological assessment of H&E-stained renal sec-
tions was consistent with the induction of mild glomerulonephritis
in CD11b-? Tg?, with increased glomerular cellularity noted (Fig.
6, A and B). This likely reflects myeloid cell expression of FcR?
rather than IC-induced activation of the CD11b-? promoter in MC
as cultured CD11b-? Tg?. MC did not demonstrate IFN-?- or
IC-induced FcR? expression (Fig. 4D). Severity of histological
activity was semiquantitatively graded using seven criteria (glo-
merular fibrinoid necrosis, 0–4; endocapillary hypercellularity,
0–4; glomerular leukocyte infiltration, 0–4; crescents, 0–4; tubu-
lar degeneration, 0–4; casts, 0–4; and interstitial inflammation,
0–4). Average scores for the groups for each of the seven cate-
gories were, respectively: WT (2.8, 3.6, 3.6, 0.6, 4.0, 4.0, 1.0);
CD11b-? Tg?(0, 2.1, 1.5, 0, 2.1, 1.9, 0); and FcR??/?(0, 0.3, 0, 0,
0, 0.2, 0). Cumulative pathological scores were 20 ? 1.2 (mean ?
SD), 2.6 ? 1.3, and 6.6 ? 1.5, for WT, FcR??/?, and CD11b-?
Tg?animals, respectively. Thus, CD11b-? Tg?animals devel-
oped an intermediate level of glomerulonephritis manifested as
increased proteinuria and histological evidence of mildly increased
glomerular endocapillary cellularity and leukocyte infiltration.
To determine whether the increased cellularity and leukocyte
infiltration were due to the glomerular recruitment of Mac-1?-
circulating monocytes/macrophages, immunostaining of renal sec-
tions was performed (Fig. 6, C and D). All three groups of mice
showed similar levels of glomerular mouse anti-sheep IgG depo-
sition, confirming that the failure to develop fulminant nephritis in
FcR??/?was not due to differences in the production and depo-
sition of anti-sheep IgG in the kidney. In the absence of activating
FcR in FcR??/?, there was no evidence of infiltrating Mac-1?
macrophages despite deposition of ICs. In WT mice, Mac-1?-in-
filtrating cells were prominent. Macrophage influx was evident as
well in CD11b-? Tg?animals, indicating that reconstitution of
activating FcR expression in CD11b/Mac-1?cells was sufficient to
restore their direct recruitment and activation in glomeruli, with
injurious consequences manifested by proteinuria.
These studies provide the rationale for the systemic delivery of
FcR-targeted therapeutics in lupus. Previous work has shown that
activating FcRs are required for nephritis pathogenesis in the au-
tologous and heterologous anti-GBM models and in spontaneous
promoter reconstitutes Ab-mediated phagocytosis in FcR??/?macro-
phages (M?). A, CD11b-FcR? construct: the murine FcR? cDNA was
inserted between the 1.7-kb 5?-flanking sequences of the human CD11b
promoter and the 3?-flanking region from the human growth hormone
gene. Three founder mice were generated, of which one expressed FcR?
in macrophages. B, Western blot analysis of FcR? expression in
CD11b? Tg?mice: whole-cell extracts were run on denaturing gels and
blotted, and the FcR? chain was detected with a rabbit anti-mouse FcR?
polyclonal Abs. Blots were stripped and reprobed with anti-?-actin
polyclonal Abs for loading controls. FcR? expression in CD11b-? Tg?
mice was seen in peritoneal macrophages but not in neutrophils, NK
cells, B cells, or T cells. C, Phagocytosis assays: rabbit IgG-opsonized
SRBCs were added to adherent peritoneal macrophages from FcR??/?
and CD11b-? Tg?mice. No phagocytosis was observed by FcR??/?
macrophages after 1 h, whereas most CD11b-? Tg?macrophages had
ingested several RBCs. D, FcR? expression in cultured MC: RT-PCR
analysis using cDNA from WT, CD11b-? Tg?, and FcR??/?MC dem-
onstrates lack of FcR? RNA expression in both FcR??/?and CD11b-?
Tg?mice in resting cells or after 24 h of stimulation with either IFN-?
(1000 U/ml) or IC (50/10 ?g/ml rabbit anti-OVA/OVA). HPRT served
as a housekeeping gene control. PMN, Polymorphonuclear cells.
Targeted re-expression of FcR? by the human CD11b
7291 The Journal of Immunology
disease in NZB/NZW. FcR??/?animals fail to develop protein-
uria and inflammatory responses despite persistent glomerular IgG
and C3 deposition (18, 19, 49, 50). In this study, we have deter-
mined the FcR-mediated contributions of intrinsic renal cells vs
circulating hemopoietic cells in disease pathogenesis. NZB/NZW
mice harboring either FcR??/?or FcR??/?BM populations de-
veloped comparable serological levels of antichromatin IgGs and
IgG/complement glomerular deposition. However inflammatory
responses and disease development were abrogated in mice con-
taining FcR??/?BM, suggesting that blockade of FcR activation
on circulating leukocytes is sufficient to limit effector responses in
lupus nephritis despite the persistence of mesangial IC deposition.
The absence of FcR? expression in recipient cells, including renal
resident cells, did not limit the incidence or severity of nephritis
development in mice bearing WT FcR? BM populations. Thus,
development of nephritis in NZB/NZW required FcR? expression
on hemopoietic cells, establishing these cells as therapeutic targets,
whereas FcR? in MC was dispensable.
To confirm that MC remained recipient derived at the time of
disease onset and progression, two experimental approaches were
used. Immunohistochemical staining of renal sections obtained at
5 and 9 mo posttransplant demonstrated persistent expression of
recipient FcR? genes and a lack of expression of donor FcR? in
MC populations. Using sensitive PCR genomic DNA assays of
short-term, enriched MC cultures obtained from mice 6 mo post-
transplant also showed that genotypically MC remained predom-
inantly of recipient origin. By 9 mo posttransplant, however, ge-
netic PCR-based evidence for replacement of some MC by BM
precursors was seen. Recent reports using GFP-expressing BM
chimeras have suggested that mesangial cell populations are re-
placed by hemopoietic precursors. However, one of these studies
involved an injury model using Thy1 Abs and in both studies only
a small fraction of MC was replaced during the observation peri-
ods (51, 52). In our studies, it is unclear whether the PCR detection
of donor FcR? alleles of enriched MC cultures resulted from re-
placement of recipient MC with hemopoietic precursors between 6
and 9 mo or resulted instead from contaminating leukocytes in
these enriched glomerular cultures. MC populations remained
mostly, if not completely, of recipient origin throughout the ob-
servation period, implying that FcRs on MC do not contribute
dominantly to the initiation of NZB/NZW lupus nephritis.
Our data are consistent with the notion that ICs deposited in
glomeruli may be directly accessible to circulating cells (15, 53,
54). In the skin and lung, by contrast, adoptive transfer studies
have demonstrated that FcR-mediated activation of tissue-resident
leukocytes in these tissues (3, 22) was sufficient to initiate inflam-
matory responses and to recruit FcR-deficient neutrophils. In the
kidney, however, the specialized endothelium in the renal glomer-
uli is fenestrated, enabling transit of plasma out of the vascular
space (55, 56). This same property also provides glomeruli the
anatomic distinction of permitting circulatory cells direct access to
tissue ICs deposited in the GBM. Thus, unlike the situation in the
skin and lung, this may permit direct initiation of the glomerular
inflammatory response by bloodborne leukocytes without a re-
quirement for resident cell-derived recruitment signals.
To determine the singular importance of activating FcR expres-
sion in monocyte/macrophage lineage cells as opposed to other
BM-derived cells in the induction of nephritis, we targeted FcR?
expression to the CD11b?compartment in FcR??/?animals.
FcR? expression by monocytes/macrophages partially reconsti-
tuted the ability to develop nephritis in the anti-GBM model, such
that significant levels of proteinuria occurred in CD11b-? Tg?
mice. The presence of activating FcRs on macrophages in
CD11b-? Tg?mice was sufficient to induce their accumulation in
renal glomeruli, presumably as a result of direct FcR activation by
glomerular ICs. Histological inflammatory changes were signifi-
cantly more intense in CD11b-? Tg?than those seen in FcR??/?.
Thus, activating FcR expression on circulating macrophage
CD11b?subsets is sufficient to induce their direct recruitment into
renal glomeruli with injurious consequences manifested by
proteinuria. Because the inflammatory response remained of mild
in macrophages is sufficient for induction of accelerated
glomerulonephritis. A, Proteinuria, urinary protein con-
tent was quantified daily and mean values of five ani-
mals per group are shown. Proteinuria differed signifi-
cantly among the groups (ANOVA, p ? 0.009). By day
7, significantly elevated proteinuria was seen in
CD11b-? Tg?mice but not in FcR??/?, ?, p ? 0.016,
CD11b-? Tg?vs FcR??/?, two-sample t test (two-
tailed). B, Serum albumin levels, serum obtained at day
7 was analyzed for serum albumin content. Serum al-
bumin was significantly different between groups
(ANOVA, p ? 0.004). Relative hypoalbuminemia oc-
curs in CD11b-??Tg mice but not in FcR??/?. The t test
p values (two-sample, two-tailed) are shown. Normal
mouse albumin is 1.6 mg/ml. Blood urea nitrogen levels,
serum obtained at day 7 was analyzed for serum urea ni-
trogen content. Uremia occurs in WT mice but not in
CD11b-??Tg mice or in FcR??/?. Uremia differed sig-
nificantly between groups (ANOVA, p ? 0.0001). The t
test p values (two-sample, two-tailed) are shown. Normal
mouse blood urea nitrogen levels were 17.3.
Lineage-restricted expression of FcR?
7292 FcR-BEARING MYELOID CELLS TRIGGER LUPUS NEPHRITIS
intensity as compared with WT animals, other FcR-bearing hemo-
poietic lineage cells must also contribute to the IC-mediated in-
flammatory nephritis, including granulocytes and CD11b?subsets
of monocytes/macrophages cell types not specifically targeted by
the CD11b-? transgene. Taken together, these studies show that
among possible FcR-bearing cell types, expression on myeloid ef-
fector cells is sufficient to convey disease susceptibility. Other
proinflammatory mediators contribute ultimately to disease (cyto-
kines, chemokines, reactive oxygen, and nitrogen species, etc.);
however, FcR engagement is likely a key proximal step in this
Our studies underscore other recent studies in the anti-GBM
model (41, 42), which suggest that direct activation of hemopoietic
FcR-bearing effectors is central to the induction of IC-triggered
nephritis. Depletion studies have demonstrated that macrophages
are critical effectors in anti-GBM nephritis (54, 57). Our data with
CD11b-? Tg?mice also support the notion that activating FcRs,
specifically on monocyte/macrophages, are pivotal to the develop-
ment of nephritis. Thus, the relative expression/function of acti-
vating and inhibitory FcRs (16, 17, 19, 58) on monocyte lineage
cells likely modulates IC-triggered glomerulonephritis. FcR-bear-
ing monocytes and macrophages may contribute directly to injury
as effectors and also indirectly by modulating IC-mediated Ag pre-
sentation and/or by facilitating recruitment and activation of lym-
phocyte effectors to the tissue site.
Systemic lupus erythematosus (SLE) is characterized by the ac-
tivation of polyclonal B and T cell self-reactive populations that
promote tissue destruction through the recruitment and activation
of inflammatory cells. In many regards, the NZB/NZW lupus ne-
phritis model shares pathogenetic features with human SLE, in-
cluding the hallmark of anti-chromatin IgG autoantibodies, female
predominance, and shared genetic disease susceptibility loci, in-
cluding the Fc?R region on chromosome 1q23, which is syntenic
in mouse and humans.
Our studies suggest that down-modulation of activating FcR
function on bloodborne leukocytes would be predicted to abrogate
the inflammatory response in human SLE potentially providing an
adjunct therapy or replacement for lymphocyte-targeted immuno-
suppression. Interestingly however, the ambiguous results of some
population studies in human SLE (reviewed in Ref. 59) suggest
discordantly that disease is associated with polymorphisms con-
veying reduced functionality of activating FcRs (Fc?RIIA-
R131(60)), Fc?RIIIA-158F (61)), or enhanced inhibitory FcR
function (FcRIIB-232Thr (62)). However, the concept that SLE is
associated paradoxically with enhanced FcR signaling is not sup-
ported by all studies, including that of Blank et al. (63), which
noted an association between SLE and an inhibitory FcRIIB pro-
moter polymorphism (?343 C/C promoter) with reduced expres-
sion. It is unclear whether these polymorphic alleles are merely
markers of other closely linked genetic contributors on chromo-
some 1 or rather indicative of hidden challenges of Fc?R-targeted
therapy that might have pleiotrophic modulatory effects on FcR
function in Ag presentation, IC catabolism, B cell regulation, as
well as myeloid effector cell-triggered inflammation.
ulonephritis with cumulative pathological scores: formalin-fixed sections were PAS stained and assessed in a blinded fashion. Pathological changes were
significantly different (ANOVA, p ? 0.0001) between groups. In CD11b-? Tg?animals, there was evidence of increased endocapillary and MC hyper-
cellularity, glomerular leukocyte infiltration, tubular degeneration, and cast formation. These changes were markedly more severe in WT mice and none
of these changes were noted in FcR??/?mice (two-sample, two-tailed t test p ? 0.002, CD11b-??Tg vs FcR??/?). C and D, Mac-1 immunostaining of
glomeruli: immunofluorescent images are shown in C and numbers of Mac-1?cells/glomerulus are quantified in D. Anti-mouse IgG stains show equivalent
amounts of IgG deposition in all three genotypes of mice. However, numbers of infiltrating Mac-1?cells varied between the groups (ANOVA, p ? 0.001).
Increased macrophage infiltration was seen in WT and CD11b-? Tg?mice but not in FcR??/?. Mac-1?cells were counted in 50 total glomeruli/
mouse and the average numbers of Mac-1?cells/glomerulus for each mouse are shown (p values determined by a two-sample, two-tailed t test are
Cd11b-? Tg?mice exhibit macrophage glomerular infiltration and mild glomerulonephritis. A and B, Histological assessment of glomer-
7293 The Journal of Immunology
We gratefully acknowledge the Transgenic Core Facility of the Herbert
Irving Cancer Center, Columbia University Medical Center and specifi-
cally Dr. Victor Lin for his help and expertise in oocyte injections and
The authors have no financial conflict of interest.
1. Sylvestre, D. L., and J. V. Ravetch. 1994. Fc receptors initiate the Arthus reac-
tion: redefining the inflammatory cascade. Science 265: 1095–1098.
2. Hazenbos, W. L., J. E. Gessner, F. M. Hofhuis, H. Kuipers, D. Meyer,
I. A. Heijnen, R. E. Schmidt, M. Sandor, P. J. Capel, M. Daeron, et al. 1996.
Impaired IgG-dependent anaphylaxis and Arthus reaction in Fc?RIII (CD16)
deficient mice. Immunity 5: 181–188.
3. Sylvestre, D. L., and J. V. Ravetch. 1996. A dominant role for mast cell Fc
receptors in the Arthus reaction. Immunity 5: 387–390.
4. Sylvestre, D., R. Clynes, M. Ma, H. Warren, M. C. Carroll, and J. V. Ravetch.
1996. Immunoglobulin G-mediated inflammatory responses develop normally in
complement-deficient mice. J. Exp. Med. 184: 2385–2392.
5. Yuasa, T., S. Kubo, T. Yoshino, A. Ujike, K. Matsumura, M. Ono, J. V. Ravetch,
and T. Takai. 1999. Deletion of Fc? receptor IIB renders H-2bmice susceptible
to collagen-induced arthritis. J. Exp. Med. 189: 187–194.
6. Kleinau, S., P. Martinsson, and B. Heyman. 2000. Induction and suppression of
collagen-induced arthritis is dependent on distinct Fc? receptors. J. Exp. Med.
7. van Lent, P. L., A. J. van Vuuren, A. B. Blom, A. E. Holthuysen,
L. B. van de Putte, J. G. van de Winkel, and W. B. van den Berg. 2000. Role of
Fc receptor ? chain in inflammation and cartilage damage during experimental
antigen-induced arthritis. Arthritis Rheum. 43: 740–752.
8. Ji, H., K. Ohmura, U. Mahmood, D. M. Lee, F. M. Hofhuis, S. A. Boackle,
K. Takahashi, V. M. Holers, M. Walport, C. Gerard, et al. 2002. Arthritis criti-
cally dependent on innate immune system players. Immunity 16: 157–168.
9. Nandakumar, K. S., M. Andren, P. Martinsson, E. Bajtner, S. Hellstrom,
R. Holmdahl, and S. Kleinau. 2003. Induction of arthritis by single monoclonal
IgG anti-collagen type II antibodies and enhancement of arthritis in mice lacking
inhibitory Fc?RIIB. Eur. J. Immunol. 33: 2269–2277.
10. Kagari, T., D. Tanaka, H. Doi, and T. Shimozato. 2003. Essential role of Fc?
receptors in anti-type II collagen antibody-induced arthritis. J. Immunol. 170:
11. Nabbe, K. C., A. B. Blom, A. E. Holthuysen, P. Boross, J. Roth, S. Verbeek,
P. L. van Lent, and W. B. van den Berg. 2003. Coordinate expression of acti-
vating Fc? receptors I and III and inhibiting Fc? receptor type II in the deter-
mination of joint inflammation and cartilage destruction during immune complex-
mediated arthritis. Arthritis Rheum. 48: 255–265.
12. Corr, M., and B. Crain. 2002. The role of Fc?R signaling in the K/B ? N serum
transfer model of arthritis. J. Immunol. 169: 6604–6609.
13. Clynes, R., J. S. Maizes, R. Guinamard, M. Ono, T. Takai, and J. V. Ravetch.
1999. Modulation of immune complex-induced inflammation in vivo by the co-
ordinate expression of activation and inhibitory Fc receptors. J. Exp. Med. 189:
14. Clynes, R., N. Calvani, B. P. Croker, and H. B. Richards. 2005. Modulation of the
immune response in pristane-induced lupus by expression of activation and in-
hibitory Fc receptors. Clin. Exp. Immunol. 141: 230–237.
15. Coxon, A., X. Cullere, S. Knight, S. Sethi, M. W. Wakelin, G. Stavrakis,
F. W. Luscinskas, and T. N. Mayadas. 2001. Fc?RIII mediates neutrophil re-
cruitment to immune complexes: a mechanism for neutrophil accumulation in
immune-mediated inflammation. Immunity 14: 693–704.
16. Tarzi, R. M., K. A. Davies, J. W. Claassens, J. S. Verbeek, M. J. Walport, and
H. T. Cook. 2003. Both Fc? receptor I and Fc? receptor III mediate disease in
accelerated nephrotoxic nephritis. Am. J. Pathol. 162: 1677–1683.
17. Radeke, H. H., I. Janssen-Graalfs, E. N. Sowa, N. Chouchakova, J. Skokowa,
F. Loscher, R. E. Schmidt, P. Heeringa, and J. E. Gessner. 2002. Opposite reg-
ulation of type II and III receptors for immunoglobulin G in mouse glomerular
mesangial cells and in the induction of anti-glomerular basement membrane
(GBM) nephritis. J. Biol. Chem. 277: 27535–27544.
18. Clynes, R., C. Dumitru, and J. V. Ravetch. 1998. Uncoupling of immune complex
formation and kidney damage in autoimmune glomerulonephritis. Science 279:
19. Suzuki, Y., I. Shirato, K. Okumura, J. V. Ravetch, T. Takai, Y. Tomino, and
C. Ra. 1998. Distinct contribution of Fc receptors and angiotensin II-dependent
pathways in anti-GBM glomerulonephritis. Kidney Int. 54: 1166–1174.
20. Godau, J., T. Heller, H. Hawlisch, M. Trappe, E. Howells, J. Best, J. Zwirner,
J. S. Verbeek, P. M. Hogarth, C. Gerard, et al. 2004. C5a initiates the inflam-
matory cascade in immune complex peritonitis. J. Immunol. 173: 3437–3445.
21. Heller, T., J. E. Gessner, R. E. Schmidt, A. Klos, W. Bautsch, and J. Kohl. 1999.
Cutting edge: Fc receptor type I for IgG on macrophages and complement me-
diate the inflammatory response in immune complex peritonitis. J. Immunol. 162:
22. Skokowa, J., S. R. Ali, O. Felda, V. Kumar, S. Konrad, N. Shushakova,
R. E. Schmidt, R. P. Piekorz, B. Nurnberg, K. Spicher, et al. 2005. Macrophages
induce the inflammatory response in the pulmonary Arthus reaction through G?i2
activation that controls C5aR and Fc receptor cooperation. J. Immunol. 174:
23. Shushakova, N., J. Skokowa, J. Schulman, U. Baumann, J. Zwirner,
R. E. Schmidt, and J. E. Gessner. 2002. C5a anaphylatoxin is a major regulator
of activating versus inhibitory Fc?Rs in immune complex-induced lung disease.
J. Clin. Invest. 110: 1823–1830.
24. Baumann, U., J. Kohl, T. Tschernig, K. Schwerter-Strumpf, J. S. Verbeek,
R. E. Schmidt, and J. E. Gessner. 2000. A codominant role of Fc?RI/III and C5aR
in the reverse Arthus reaction. J. Immunol. 164: 1065–1070.
25. Kaplan, C. D., S. K. O’Neill, T. Koreny, M. Czipri, and A. Finnegan. 2002.
Development of inflammation in proteoglycan-induced arthritis is dependent on
Fc?R regulation of the cytokine/chemokine environment. J. Immunol. 169:
26. Wipke, B. T., Z. Wang, W. Nagengast, D. E. Reichert, and P. M. Allen. 2004.
Staging the initiation of autoantibody-induced arthritis: a critical role for immune
complexes. J. Immunol. 172: 7694–7702.
27. Lee, D. M., D. S. Friend, M. F. Gurish, C. Benoist, D. Mathis, and M. B. Brenner.
2002. Mast cells: a cellular link between autoantibodies and inflammatory arthri-
tis. Science 297: 1689–1692.
28. Taube, C., A. Dakhama, Y. H. Rha, K. Takeda, A. Joetham, J. W. Park,
A. Balhorn, T. Takai, K. R. Poch, J. A. Nick, and E. W. Gelfand. 2003. Transient
neutrophil infiltration after allergen challenge is dependent on specific antibodies
and Fc?III receptors. J. Immunol. 170: 4301–4309.
29. Zhang, Y., B. F. Ramos, and B. A. Jakschik. 1992. Neutrophil recruitment by
tumor necrosis factor from mast cells in immune complex peritonitis. Science
30. Ramos, B. F., Y. Zhang, R. Qureshi, and B. A. Jakschik. 1991. Mast cells are
critical for the production of leukotrienes responsible for neutrophil recruitment
in immune complex-induced peritonitis in mice. J. Immunol. 147: 1636–1641.
31. Gomez-Guerrero, C., O. Lopez-Franco, G. Sanjuan, P. Hernandez-Vargas,
Y. Suzuki, G. Ortiz-Munoz, J. Blanco, and J. Egido. 2004. Suppressors of cyto-
kine signaling regulate Fc receptor signaling and cell activation during immune
renal injury. J. Immunol. 172: 6969–6977.
32. Gomez-Guerrero, C., O. Lopez-Franco, Y. Suzuki, G. Sanjuan, P. Hernandez-
Vargas, J. Blanco, and J. Egido. 2002. Nitric oxide production in renal cells by
immune complexes: role of kinases and nuclear factor-?B. Kidney Int. 62:
33. Gomez-Guerrero, C., P. Hernandez-Vargas, O. Lopez-Franco, G. Ortiz-Munoz,
and J. Egido. 2005. Mesangial cells and glomerular inflammation: from the
pathogenesis to novel therapeutic approaches. Curr. Drug Targets 4: 341–351.
34. Lopez-Armada, M. J., C. Gomez-Guerrero, and J. Egido. 1996. Receptors for
immune complexes activate gene expression and synthesis of matrix proteins in
cultured rat and human mesangial cells: role of TGF-?. J. Immunol. 157:
35. Morcos, M., G. M. Hansch, M. Schonermark, S. Ellwanger, M. Harle, and
B. Heckl-Ostreicher. 1994. Human glomerular mesangial cells express CD16 and
may be stimulated via this receptor. Kidney Int. 46: 1627–1634.
36. Uciechowski, P., M. Schwarz, J. E. Gessner, R. E. Schmidt, K. Resch, and
H. H. Radeke. 1998. IFN-? induces the high-affinity Fc receptor I for IgG (CD64)
on human glomerular mesangial cells. Eur. J. Immunol. 28: 2928–2935.
37. Hora, K., J. A. Satriano, A. Santiago, T. Mori, E. R. Stanley, Z. Shan, and
D. Schlondorff. 1992. Receptors for IgG complexes activate synthesis of mono-
cyte chemoattractant peptide 1 and colony-stimulating factor 1. Proc. Natl. Acad.
Sci. USA 89: 1745–1749.
38. Singhal, P. C., S. Gupta, P. Sharma, H. Shah, N. Shah, and P. Patel. 2000.
Receptor mediated endocytosis by mesangial cells modulates transmigration of
macrophages. Inflammation 24: 519–532.
39. Gomez-Guerrero, C., M. J. Lopez-Armada, E. Gonzalez, and J. Egido. 1994.
Soluble IgA and IgG aggregates are catabolized by cultured rat mesangial cells
and induce production of TNF-? and IL-6, and proliferation. J. Immunol. 153:
40. Kovalenko, P., H. Fujinaka, Y. Yoshida, H. Kawamura, Z. Qu, A. G. El-Shemi,
H. Li, A. Matsuki, V. Bilim, E. Yaoita, et al. 2004. Fc receptor-mediated accu-
mulation of macrophages in crescentic glomerulonephritis induced by anti-
glomerular basement membrane antibody administration in WKY rats. Int.
Immunol. 16: 625–634.
41. Suzuki, Y., C. Gomez-Guerrero, I. Shirato, O. Lopez-Franco, J. Gallego-Delgado,
G. Sanjuan, A. Lazaro, P. Hernandez-Vargas, K. Okumura, Y. Tomino, et al. 2003.
Pre-existing glomerular immune complexes induce polymorphonuclear cell recruit-
ment through an Fc receptor-dependent respiratory burst: potential role in the per-
petuation of immune nephritis. J. Immunol. 170: 3243–3253.
42. Tarzi, R. M., K. A. Davies, M. G. Robson, L. Fossati-Jimack, T. Saito,
M. J. Walport, and H. T. Cook. 2002. Nephrotoxic nephritis is mediated by Fc?
receptors on circulating leukocytes and not intrinsic renal cells. Kidney Int. 62:
43. Wirthmueller, U., T. Kurosaki, M. S. Murakami, and J. V. Ravetch. 1992. Signal
transduction by Fc?RIII (CD16) is mediated through the ?-chain. J. Exp. Med.
44. Dziennis, S., R. A. Van Etten, H. L. Pahl, D. L. Morris, T. L. Rothstein,
C. M. Blosch, R. M. Perlmutter, and D. G. Tenen. 1995. The CD11b promoter
directs high-level expression of reporter genes in macrophages in transgenic
mice. [Published erratum appears in 1995 Blood 85: 1983.] Blood 85: 319–329.
45. Hogarth, M. B., P. J. Norsworthy, P. J. Allen, P. K. Trinder, M. Loos,
B. J. Morley, M. J. Walport, and K. A. Davies. 1996. Autoantibodies to the
collagenous region of C1q occur in three strains of lupus-prone mice. Clin. Exp.
Immunol. 104: 241–246.
7294 FcR-BEARING MYELOID CELLS TRIGGER LUPUS NEPHRITIS
46. Uwatoko, S., M. Mannik, I. R. Oppliger, M. Okawa-Takatsuji, S. Aotsuka,
R. Yokohari, G. Seki, S. Taniguchi, K. Suzuki, and K. Kurokawa. 1995. C1q-
binding immunoglobulin G in MRL/l mice consists of immune complexes con-
taining antibodies to DNA. Clin. Immunol. Immunopathol. 75: 140–146.
47. Luo, Y., C. Lloyd, J. C. Gutierrez-Ramos, and M. E. Dorf. 1999. Chemokine
amplification in mesangial cells. [Published erratum appears in 2000 J. Immunol.
164: 5332.] J. Immunol. 163: 3985–3992.
48. Takai, T., M. Li, D. Sylvestre, R. Clynes, and J. V. Ravetch. 1994. FcR ? chain
deletion results in pleiotrophic effector cell defects. Cell 76: 519–529.
49. Wakayama, H., Y. Hasegawa, T. Kawabe, T. Hara, S. Matsuo, M. Mizuno,
T. Takai, H. Kikutani, and K. Shimokata. 2000. Abolition of anti-glomerular
basement membrane antibody-mediated glomerulonephritis in FcR?-deficient
mice. Eur. J. Immunol. 30: 1182–1190.
50. Park, S. Y., S. Ueda, H. Ohno, Y. Hamano, M. Tanaka, T. Shiratori, T. Yamazaki,
H. Arase, N. Arase, A. Karasawa, et al. 1998. Resistance of Fc receptor- deficient
mice to fatal glomerulonephritis. J. Clin. Invest. 102: 1229–1238.
51. Ito, T., A. Suzuki, E. Imai, M. Okabe, and M. Hori. 2001. Bone marrow is a
reservoir of repopulating mesangial cells during glomerular remodeling. J. Am.
Soc. Nephrol. 12: 2625–2635.
52. Imasawa, T., Y. Utsunomiya, T. Kawamura, Y. Zhong, R. Nagasawa, M. Okabe,
N. Maruyama, T. Hosoya, and T. Ohno. 2001. The potential of bone marrow-
derived cells to differentiate to glomerular mesangial cells. J. Am. Soc. Nephrol.
53. Tang, T., A. Rosenkranz, K. J. Assmann, M. J. Goodman, J. C. Gutierrez-Ramos,
M. C. Carroll, R. S. Cotran, and T. N. Mayadas. 1997. A role for Mac-1 (CDIIb/
CD18) in immune complex-stimulated neutrophil function in vivo: Mac-1 defi-
ciency abrogates sustained Fc? receptor-dependent neutrophil adhesion and com-
plement-dependent proteinuria in acute glomerulonephritis. J. Exp. Med. 186:
54. Ikezumi, Y., L. A. Hurst, T. Masaki, R. C. Atkins, and D. J. Nikolic-Paterson.
2003. Adoptive transfer studies demonstrate that macrophages can induce pro-
teinuria and mesangial cell proliferation. Kidney Int. 63: 83–95.
55. Lea, P. J., M. Silverman, R. Hegele, and M. J. Hollenberg. 1989. Tridimensional
ultrastructure of glomerular capillary endothelium revealed by high-resolution
scanning electron microscopy. Microvasc. Res. 38: 296–308.
56. Drumond, M. C., and W. M. Deen. 1994. Structural determinants of glomerular
hydraulic permeability. Am. J. Physiol. 266: F1–F12.
57. Huang, X. R., P. G. Tipping, J. Apostolopoulos, C. Oettinger, M. D’Souza,
G. Milton, and S. R. Holdsworth. 1997. Mechanisms of T cell-induced glomer-
ular injury in anti-glomerular basement membrane (GBM) glomerulonephritis in
rats. Clin. Exp. Immunol. 109: 134–142.
58. Fujii, T., Y. Hamano, S. Ueda, B. Akikusa, S. Yamasaki, M. Ogawa, H. Saisho,
J. S. Verbeek, S. Taki, and T. Saito. 2003. Predominant role of Fc?RIII in the
induction of accelerated nephrotoxic glomerulonephritis. Kidney Int. 64:
59. Takai, T. 2005. Fc receptors and their role in immune regulation and autoimmu-
nity. J. Clin. Immunol. 25: 1–18.
60. Salmon, J. E., S. Millard, L. A. Schachter, F. C. Arnett, E. M. Ginzler,
M. F. Gourley, R. Ramsey-Goldman, M. G. Peterson, and R. P. Kimberly. 1996.
Fc?RIIA alleles are heritable risk factors for lupus nephritis in African Ameri-
cans. J. Clin. Invest. 97: 1348–1354.
61. Wu, J., J. C. Edberg, P. B. Redecha, V. Bansal, P. M. Guyre, K. Coleman,
J. E. Salmon, and R. P. Kimberly. 1997. A novel polymorphism of Fc?RIIIa
(CD16) alters receptor function and predisposes to autoimmune disease. J. Clin.
Invest. 100: 1059–1070.
62. Li, X., J. Wu, R. H. Carter, J. C. Edberg, K. Su, G. S. Cooper, and R. P. Kimberly.
2003. A novel polymorphism in the Fc? receptor IIB (CD32B) transmembrane
region alters receptor signaling. Arthritis Rheum. 48: 3242–3252.
63. Blank, M. C., R. N. Stefanescu, E. Masuda, F. Marti, P. D. King, P. B. Redecha,
R. J. Wurzburger, M. G. Peterson, S. Tanaka, and L. Pricop. 2005. Decreased
transcription of the human FCGR2B gene mediated by the ?343 G/C promoter
polymorphism and association with systemic Lupus Erythematosus. Hum. Genet.
7295 The Journal of Immunology