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BCR crosslinking induced calcium flux. Single-cell suspensions from spleen were stained for IgM and IgD. After incubation with CalbryteTM 520 AM, separate samples were treated with various concentrations of polyclonal anti-IgM, or anti-Ig-kappa F(ab′) 2, as indicated. Calcium flux was measured by flow cytometry (LSRII, BD, using a Flow Jo 10.7.1 software). a Representative histogram plots for IgMhigh/IgDlow naive B cells and IgMhigh/IgDlow marginal zone B cells, as indicated. b Statistical analysis of calcium flux after incubation with increasing concentrations of polyclonal anti-IgM F(ab′)2, for IgMhigh/IgDlow naive B cells, IgMhigh/IgDlow marginal zone B cells and IgMneg/IgDneg cells. Each symbol represents one cell culture well (n = 5 for all conditions). Representative data from one of three independent experiments, median and range are indicated. No sample was excluded from the analysis. Statistics: Friedmann-Test was calculated using R. ***p ≤ 0.001.
Source publication
Mutated and unmutated IgE and IgG play different and partly opposing roles in allergy development, but the mechanisms controlling their relative production are incompletely understood. Here, we analyzed the IgE-response in murine food allergy. Deep sequencing of the complementary-determining region (CDR) repertoires indicated that an ongoing unmuta...
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Context 1
... anti-IgM and anti-Ig kappa F(ab')2 induced a dosedependent calcium flux (Fig. 5), indicating that titrated concentrations of these reagents can mimic the differential signal strength that would characterize Ag stimulation of low or high-affinity Fig. 4 Physiochemical properties of IgE G and IgE E . Sequences from mLN and BM of allergic mice were analyzed after 13 o.g. allergen challenges. Physiochemical properties ...
Context 2
... anti-IgM and anti-Ig kappa F(ab')2 induced a dosedependent calcium flux (Fig. 5), indicating that titrated concentrations of these reagents can mimic the differential signal strength that would characterize Ag stimulation of low or high-affinity Fig. 4 Physiochemical properties of IgE G and IgE E . Sequences from mLN and BM of allergic mice were analyzed after 13 o.g. allergen challenges. Physiochemical properties ...
Citations
... Concurrently, decreased IFN-γ levels weaken regulatory mechanisms that typically suppress the Th2 response and limit IgE production. This imbalance perpetuates the inflammatory cascade, exacerbating AD symptoms [22]. Reduction in IgE levels and alteration of the Th1/Th2 balance explain the improvement in skin symptoms and reduction in itching behavior. ...
Canine atopic dermatitis (CAD) is a common chronic allergic skin disease. In our previous study, we isolated two probiotic strains, Lactococcus cremoris subsp. cremoris MP01 and Lacticaseibacillus paracasei subsp. paracasei MP02, from Mongolian fermented milk. These strains demonstrated potential in alleviating symptoms similar to AD and reducing specific immunoglobulin E (IgE) levels in a mouse model of AD. Building upon this discovery, our current investigation sought to evaluate the therapeutic potential of these probiotics for treating CAD. We conducted an open-label, single-arm clinical trial where dogs diagnosed with AD were administered LCP capsules containing Lc. cremoris subsp. cremoris MP01 and L. paracasei subsp. paracasei MP02 once daily for 60 days. Stool, skin swab, and venous blood specimens were collected at three intervals: before, and after 30 and 60 days of LCP intervention. The skin and fecal microbiomes were analyzed using full-length 16S rRNA sequencing. After 60 days of LCP intervention, notable improvements were observed in skin lesions and scratching behaviors, accompanied by reductions in both the Canine Atopic Dermatitis Extent and Severity Index (CADESI) and the Pruritus Visual Analogue Scale (PVAS) scores. Additionally, LCP intervention resulted in significant reductions in IgE levels and modulation in type 1 T helper (Th1)/ type 2 T helper cells (Th2)-related cytokine secretion. Microbiota analysis unveiled changes in the composition of both skin and gut microbiotas, including reductions in Shigella flexneri on the skin and Romboutsia in the gut. Levels of short-chain fatty acid (SCFA) increased following the 60-days of LCP intervention. These effects were likely mediated by alterations in gut microbiota and the upregulation of SCFA levels, which subsequently reduced the secretion of allergy-related IgE. Collectively, these mechanisms contributed to alleviating CAD symptoms, regulating skin microbiota composition, and reducing the adherence and invasion of environmental microbes and pathogens. Overall, our findings highlight the promising therapeutic potential of the Lc. cremoris subsp. cremoris MP01 and L. paracasei subsp. paracasei MP02 mixture as an effective strategy for managing CAD in dogs.
... The ratios between the levels of allergen specific IgE and the levels of allergen specific antibodies of other subclasses, correlate better with the development of severe allergic symptoms than the levels of IgE alone. 5 This reflects the fact that antibodies of other subclasses such as IgG1 or IgA can inhibit the severe allergic reactions induced by high-affinity IgE. ...
... Therefore, their antigen-binding sites share the same fine specificity which might be important for efficient competition for allergen binding. In the body fluids, IgG antibodies are present at very higher levels, typically exceeding that of IgE approximately 100 fold or more [35]. The unique blocking properties of IgG4 are associated with their ability to form a Fab arm exchange which allows bispecific antigen recognition thereby interrupting the crosslinking of identical antigens and preventing the formation of immune complexes [77]. ...
... Though extrafollicular B cell differentiation might be mainly important during the initial response, it seems to persist for longer periods at least on low level. In a murine model to food allergy, approximately 5% of IgE clones with a considerable expansion rate (more than 50 copies per clone) did not show signs of hypermutation, even after repeated and long-lasting allergen challenge [35], hence indicating that an extrafollicular response could continue on a low level during established allergy. The extent to which this unmutated, low-affinity IgE may contribute to the inhibition of allergic symptoms has been described above but remains to be further elucidated. ...
... Though extrafollicular B cell differentiation might be mainly important during the initial response, it seems to persist for longer periods at least on low level. In a murine model to food allergy, approximately 5% of IgE clones with a considerable expansion rate (more than 50 copies per clone) did not show signs of hypermutation, even after repeated and long-lasting allergen challenge [35], hence indicating that an extrafollicular response could continue on a low level during established allergy. The extent to which this unmutated, lowaffinity IgE may contribute to the inhibition of allergic symptoms has been described above but remains to be further elucidated. ...
Simple Summary: It has long been known that antibodies of a certain class, called IgE, are the main cause of allergic reactions to food. Other antibody types such as IgA and IgG can suppress the allergic reaction. Even IgE, which binds the allergen only weakly (i.e., with low affinity), seems to have a protective effect. This review discusses the role of distinct antibody types in food allergy, and the underlying mechanisms of action. These findings might be important to understand the development and course of food allergies, and could help to improve diagnostics and therapy. Abstract: Food allergies are a growing public health concern worldwide, especially in children and young adults. Allergen-specific IgE plays a central role in the pathogenesis of food allergies, but their titers poorly correlate with allergy development. Host immune systems yield allergen-specific immunoglobulin (Ig)A, IgE and IgG subclasses with low or high affinities and differential Fc N-glycosylation patterns that can affect the allergic reaction to food in multiple ways. High-affinity IgE is required to induce strong mast cell activation eventually leading to allergic anaphylaxis, while low-affinity IgE can even inhibit the development of clinically relevant allergic symptoms. IgA and IgG antibodies can inhibit IgE-mediated mast cell activation through various mechanisms, thereby protecting IgE-positive individuals from allergy development. The production of IgE and IgG with differential allergenic potential seems to be affected by the signaling strength of individual B cell receptors, and by cytokines from T cells. This review provides an overview of the diversity of the B cell response and the diverse roles of antibodies in food allergy.
... Indeed, other studies involving mouse models of food allergy induced by proteins have shown similar results to our study, in that murine IgG 1 was induced together with IgE. 55,56 Moreover, although the transfer of total IgG from allergic mice to recipients dampened the allergic response, IgG 1 alone did not cause this effect. 56 Thus, murine IgG 1 does not share the tolerance-favoring attributes of human IgG 4 in allergic inflammation. ...
Background
Alpha-gal (Galα1-3Galβ1-4GlcNAc) is a carbohydrate with the potential to elicit fatal allergic reactions to mammalian meat and drugs of mammalian origin. This type of allergy is induced by tick bites, and therapeutic options for this skin-driven food allergy are limited to the avoidance of the allergen and treatment of symptoms. Thus, a better understanding of the immune mechanisms resulting in sensitization through the skin is crucial, especially in the case of a carbohydrate allergen for which underlying immune responses are poorly understood.
Objective
We aimed to establish a mouse model of alpha-gal allergy for in-depth immunologic analyses.
Methods
Alpha-galactosyltransferase 1–deficient mice devoid of alpha-gal glycosylations were sensitized with the alpha-gal–carrying self-protein mouse serum albumin by repetitive intracutaneous injections in combination with the adjuvant aluminum hydroxide. The role of basophils and IL-4 in sensitization was investigated by antibody-mediated depletion.
Results
Alpha-gal–sensitized mice displayed increased levels of alpha-gal–specific IgE and IgG1 and developed systemic anaphylaxis on challenge with both alpha-gal–containing glycoproteins and glycolipids. In accordance with alpha-gal–allergic patients, we detected elevated numbers of basophils at the site of sensitization as well as increased numbers of alpha-gal–specific B cells, germinal center B cells, and B cells of IgE and IgG1 isotypes in skin-draining lymph nodes. By depleting IL-4 during sensitization, we demonstrated for the first time that sensitization and elicitation of allergy to alpha-gal and correspondingly to a carbohydrate allergen is dependent on IL-4.
Conclusion
These findings establish IL-4 as a potential target to interfere with alpha-gal allergy elicited by tick bites.
Mechanisms that restrict class switch recombination (CSR) to IgE limit the subsequent production of IgE antibodies and therefore the development of allergic disease. Mice with impaired B cell receptor (BCR) signaling have significantly increased IgE responses, consistent with a role for BCR signaling in IgE regulation. While prior work focused on BCR signaling in IgE-expressing cells to explain these findings, it has been reported that BCR signaling can reduce CSR. Therefore, we investigated the possibility that IgE CSR might be particularly sensitive to inhibition by BCR signaling in unswitched B cells. We found that immunization of mice with high-affinity antigen resulted in reduced representation of IgE-expressing cells among germinal center B cells and plasma cells relative to a low-affinity antigen. Mechanistic experiments with cultured mouse B cells demonstrated that BCR ligands selectively inhibited IgE CSR in a dose-, affinity-, and avidity-dependent manner. Signaling via Syk was required for the inhibition of IgE CSR following BCR stimulation, whereas inhibition of the PI3K subunit p110δ increased IgE CSR independently of BCR ligation. The inhibition of IgE CSR by BCR ligands synergized with IL-21 or TGFβ1. BCR ligation also inhibited CSR to IgE in human tonsillar B cells, and this inhibition was also synergistic with IL-21 or TGFβ1. These findings establish that IgE CSR is uniquely susceptible to inhibition by BCR signaling in mouse and human B cells, with important implications for the regulation and pathogenesis of allergic disease.
Despite the near ubiquitous presence of Ig‐based antibodies in vertebrates, IgE is unique to mammals. How and why it emerged remains mysterious. IgE expression is greatly constrained compared to other IgH isotypes. While other IgH isotypes are relatively abundant, soluble IgE has a truncated half‐life, and IgE plasma cells are mostly short‐lived. Despite its rarity, IgE is consequential and can trigger life‐threatening anaphylaxis. IgE production reflects a dynamic steady state with IgG memory B cells feeding short‐lived IgE production. Emerging evidence suggests that IgE may also potentially be produced in longer‐lived plasma cells as well, perhaps as an aberrancy stemming from its evolutionary roots from an antibody isotype that likely functioned more like IgG. As a late derivative of an ancient systemic antibody system, the benefits of IgE in mammals likely stems from the antibody system's adaptive recognition and response capability. However, the tendency for massive, systemic, and long‐lived production, common to IgH isotypes like IgG, were likely not a good fit for IgE. The evolutionary derivation of IgE from an antibody system that for millions of years was good at antigen de‐sensitization to now functioning as a highly specialized antigen‐sensitization function required heavy restrictions on antibody production—insufficiency of which may contribute to allergic disease.
The existence of long‐lived IgE antibody‐secreting cells (ASC) is contentious, with the maintenance of sensitization by the continuous differentiation of short‐lived IgE⁺ ASC a possibility. Here, we review the epidemiological profile of IgE production, and give an overview of recent discoveries made on the mechanisms regulating IgE production from mouse models. Together, these data suggest that for most individuals, in most IgE‐associated diseases, IgE⁺ ASC are largely short‐lived cells. A subpopulation of IgE⁺ ASC in humans is likely to survive for tens of months, although due to autonomous IgE B cell receptor (BCR) signaling and antigen‐driven IgE⁺ ASC apoptosis, in general IgE⁺ ASC probably do not persist for the decades that other ASC are inferred to do. We also report on recently identified memory B cell transcriptional subtypes that are the likely source of IgE in ongoing responses, highlighting the probable importance of IL‐4Rα in their regulation. We suggest the field should look at dupilumab and other drugs that prohibit IgE⁺ ASC production as being effective treatments for IgE‐mediated aspects of disease in most individuals.
Background
Allergic airway disease (AAD) is a chronic disease characterized by airway inflammation, bronchoconstriction, and hyperresponsiveness. Although exogenous interleukin-10 (IL-10) alleviates allergic inflammation, it has a short half-life in vivo. Cell membrane-coated nanomaterials have been shown to protect therapeutic payloads and increase therapeutic efficacy.
Objective
This study was aimed at investigating the efficacy of a novel macrophage-based nanoparticle drug for the treatment of house dust mite (HDM)-induced allergic airway diseases.
Methods
IL-10-poly (lactic-co-glycolic acid (PLGA) nanoparticles were encapsulated in alveolar macrophage cell membranes. An allergic airway disease mouse model was established by repeated inhalation of HDM extracts. The mice were treated with free IL-10, IL-10-PLGA nanoparticles (IL10-NP), or IL-10-alveolar macrophage cell membrane-coated nanoparticles (IL10-AMNP). The therapeutic effects were evaluated by measuring airway hyperresponsiveness, lung inflammation, cytokine levels, and regulatory T cells (Treg)- T-helper 17 (Th17) cell balance.
Results
Compared to free IL-10, IL10-AMNP significantly reduced airway hyperresponsiveness and T-helper 2 (Th2)/Th17 cytokines and inhibited neutrophilia and eosinophilia recruitment into the airways of HDM-induced mouse models. Additionally, the balance between Tregs and Th17 cells was significantly improved in groups treated with IL10-AMNP.
Conclusion
This study demonstrated that PLGA nanoparticle cores coated with alveolar macrophage cell membranes can effectively deliver therapeutic cytokines to the lungs and improve the homeostatic balance between Tregs and Th17 cells. These findings suggest that macrophage-based nanoparticle drugs represent a promising approach for treating allergic airway diseases.
