IgE-mediated Chronic Allergic Inflammation Research Articles

Aggregation makes a protein allergenic at the challenge phase of basophil-mediated allergy in mice.

A hapten is a small molecule that is not immunogenic on its own but can stimulate the production of antibodies at the sensitization phase when conjugated to carrier proteins. The hapten then reacts specifically with the antibodies generated against it to elicit an immune or allergic response at the challenge phase. Here, we compared various carrier proteins conjugated with the same hapten in their ability to induce hapten-specific IgE-mediated allergic responses in vitro and in vivo, and characterized the nature of carrier proteins that determines the magnitude of response at the challenge phase of allergic reactions. Hapten 2,4,6-trinitrophenol (TNP)-conjugated ovalbumin (TNP-OVA) and bovine serum albumin (TNP-BSA) elicited TNP-specific, mast cell-dependent, immediate-type allergic reactions at a comparable level in mice that had been passively sensitized with TNP-specific IgE. In contrast, TNP-OVA but not TNP-BSA efficiently induced a basophil-dependent, IgE-mediated chronic allergic inflammation (IgE-CAI), even though both proteins could stimulate basophils in vitro at a comparable level. By comparing different carrier proteins and structurally modifying them, we found that the formation of large aggregates is crucial for TNP-conjugated carrier proteins to efficiently elicit IgE-CAI, regardless of the type of protein. Thus, the aggregation status of carrier proteins appears to determine the magnitude of allergic response at the challenge phase of hapten-specific IgE-CAI. Our findings suggest that the allergenicity of substances is a matter of importance not only at the sensitization but also at the challenge phase in a certain type of allergy including a basophil-mediated allergic inflammation.

Identification of Secretory Leukoprotease Inhibitor As an Endogenous Negative Regulator in Allergic Effector Cells.

Mast cells, basophils, and eosinophils are central effectors in allergic inflammatory disorders. These cells secrete abundant serine proteases as well as chemical mediators and cytokines; however, the expression profiles and functions of their endogenous inhibitors remain elusive. We found that murine secretory leukoprotease inhibitor (SLPI) is expressed in basophils and eosinophils but in not in mast cells. SLPI-deficient (Slpi−/−) basophils produce more cytokines than wild-type mice after IgE stimulation. Although the deletion of SLPI in basophils did not affect the release of chemical mediators upon IgE stimulation, the enzymatic activity of the serine protease tryptase was increased in Slpi−/− basophils. Mice transferred with Slpi−/− basophils were highly sensitive to IgE-mediated chronic allergic inflammation. Eosinophils lacking SLPI showed greater interleukin-6 secretion and invasive activity upon lipopolysaccharide stimulation, and the expression of matrix metalloproteinase-9 by these eosinophils was increased without stimulation. The absence of SLPI increases JNK1 phosphorylation at the steady state, and augments the serine phosphorylation of JNK1-downstream ETS transcriptional factor Elk-1 in eosinophils upon stimulation. Of note, SLPI interacts with a scaffold protein, JNK-interacting protein 3 (JIP3), that constitutively binds to the cytoplasmic domain of toll-like receptor (TLR) 4, suggesting that SLPI controls Elk-1 activation via binding to JIP3 in eosinophils. Mice transferred with Slpi−/− eosinophils showed the exacerbation of chitin-induced allergic inflammation. These findings showed that SLPI is a negative regulator in allergic effector cells and suggested a novel inhibitory role of SLPI in the TLR4 signaling pathways.

Basophils require interaction with CD49b(+)/c-kit(+) cells through L-selectin for induction of IgE-mediated chronic allergic inflammation

Basophils require interaction with CD49b(+)/c-kit(+) cells through L-selectin for induction of IgE-mediated chronic allergic inflammation

α(1,3) Fucosyltransferases IV and VII Are Essential for the Initial Recruitment of Basophils in Chronic Allergic Inflammation

Basophils act as initiator cells for the development of IgE-mediated chronic allergic inflammation (IgE-CAI). However, detailed mechanisms of initial recruitment of basophils into the skin have yet to be clarified. Selectins mediate leukocyte capture and rolling on the vascular endothelium for extravasation. Counter-receptor activity of selectins is regulated by α(1, 3) fucosyltransferases (FTs) IV and VII. To clarify the contribution of selectin ligands regulated by FTs for initial basophil recruitment, IgE-CAI was induced in mice deficient in FT-IV and/or FT-VII genes. Although FT-IV(-/-) and FT-VII(-/-) mice exhibited comparable skin responses to wild-type mice, the FT-IV(-/-)/FT-VII(-/-) mice showed significantly impaired inflammation. Although the transfer of basophils to FcRγ(-/-) mice induced IgE-CAI, this induction was completely absent when basophils from FT-IV(-/-)/FT-VII(-/-) mice were transferred. L-selectin, but not P- and E-selectin, blocking Abs inhibited skin inflammation in vivo. P-selectin glycoprotein-1 (PSGL-1) antibody also ameliorated skin inflammation, and basophils were bound to L-selectin in a PSGL-1-dependent manner, which was regulated by FT-IV/VII. Functional PSGL-1 generated by basophil FT-IV/VII and its subsequent binding to L-selectin could be one of the essential steps required for initial basophil recruitment and the development of IgE-CAI in mice.

The basophil: Resolved questions and new avenues of investigation

The contribution that the subset of leukocytes known as basophils makes to immunity is controversial. A clear picture of the function of basophils has been slow to emerge, mainly due to functional studies on basophils in vivo being hampered by limitations in reagent availability and specificity. These issues were discussed by Schwartz and Voehringer in the June 2011 issue of BioEssays 1. The authors speculated that many outstanding issues surrounding basophil function would soon be resolved following recent development of specific means to delete and track basophils in vivo. Indeed, in subsequent months more definitive determination of basophil function has emerged using these tools. Thus, we here provide a brief update on the function of basophils in immunity. Whether basophils serve as antigen-presenting cells (APCs) that prime TH2 cell responses, the T cell subset controlling allergic and anti-parasitic immunity, was controversial 1. Sullivan and colleagues demonstrated that basophils do not play an essential role in the priming of TH2 cells following Schistosoma mansoni egg infection or in the papain-induced model of allergy 2. Moreover, their data revealed that basophils do not form stable conjugates with antigen-specific T cells, a prerequisite for an effective APC. The same study addressed another controversy pertaining to the function of basophils as effector cells in host defense against parasites. It was demonstrated that basophils provide a non-redundant source of IL-4 in infected tissues, which, in collaboration with T cell-derived IL-4, mediated worm expulsion following Nippostrongylus brasiliensis infection 2. Thus, a picture is now emerging whereby anti-parasitic immunity is not reliant on basophils as APCs, but requires cooperative responses between basophils and CD4+ T cells as effector cells. One explanation for discrepancies regarding reported functions of basophils may also be explained by recent findings demonstrating significant heterogeneity in basophils. Whilst IL-3 has long been considered the critical factor mediating basophil differentiation, recent studies have identified a novel function for the cytokine thymic stromal lymphopoetin (TSLP), which drives production of basophils distinct from those reliant on IL-3 3, 4. These studies further demonstrated that peripheral basophillia in murine models of atopic dermatitis and Trichinella spiralis infection are TSLP-dependent and can occur in the presence or absence of IL-3, raising the question of whether specific subtypes of basophils mediate distinct responses. Basophils have also been implicated as important effector cells driving pathogenesis of IgE-mediated chronic allergic inflammation (IgE-CAI) of the skin. However, recent work using new genetic tools to delete basophils surprisingly identified an anti-inflammatory role of basophils in this setting. Egawa et al. 5 demonstrated that basophils promoted differentiation of inflammatory monocytes into anti-inflammatory M2 macrophages rather than typical inflammatory M1 macrophages. Basophil-induced M2 macrophage differentiation subsequently dampened allergic inflammation during IgE-CAI. Thus, an intriguing possibility now emerges that basophils function as important regulators of macrophage differentiation in a range of inflammatory settings, which could have important implications for treatment in various inflammatory pathologies. Thus, as the important questions regarding the function of basophils in mice begin to be definitively addressed with novel genetic tools, new questions arise. Are there subsets of basophils yet to be identified that are capable of acting as APCs? Does boosting basophil responses provide a means to control macrophage-driven inflammation? Finally, and crucially, do these findings with regard to basophils in murine experimental models accurately reflect the functional significance of basophils in humans?

Novel Basophil- or Eosinophil-Depleted Mouse Models for Functional Analyses of Allergic Inflammation

Basophils and eosinophils play important roles in various host defense mechanisms but also act as harmful effectors in allergic disorders. We generated novel basophil- and eosinophil-depletion mouse models by introducing the human diphtheria toxin (DT) receptor gene under the control of the mouse CD203c and the eosinophil peroxidase promoter, respectively, to study the critical roles of these cells in the immunological response. These mice exhibited selective depletion of the target cells upon DT administration. In the basophil-depletion model, DT administration attenuated a drop in body temperature in IgG-mediated systemic anaphylaxis in a dose-dependent manner and almost completely abolished the development of ear swelling in IgE-mediated chronic allergic inflammation (IgE-CAI), a typical skin swelling reaction with massive eosinophil infiltration. In contrast, in the eosinophil-depletion model, DT administration ameliorated the ear swelling in IgE-CAI whether DT was administered before, simultaneously, or after, antigen challenge, with significantly lower numbers of eosinophils infiltrating into the swelling site. These results confirm that basophils and eosinophils act as the initiator and the effector, respectively, in IgE-CAI. In addition, antibody array analysis suggested that eotaxin-2 is a principal chemokine that attracts proinflammatory cells, leading to chronic allergic inflammation. Thus, the two mouse models established in this study are potentially useful and powerful tools for studying the in vivo roles of basophils and eosinophils. The combination of basophil- and eosinophil-depletion mouse models provides a new approach to understanding the complicated mechanism of allergic inflammation in conditions such as atopic dermatitis and asthma.

Basophil-derived mouse mast cell protease 11 is involved in the development of IgE-mediated chronic allergic inflammation

Event Abstract Back to Event Basophil-derived mouse mast cell protease 11 is involved in the development of IgE-mediated chronic allergic inflammation Hayato DEKI1, Yohei KAWANO1, Soichro YOSHIKAWA1, Mayumi EGAWA1, Misako IKI1 and Hajime KARASUYAMA1* 1 Tokyo Medical and Dental University, Japan Basophils are the least common granulocytes, and had long been considered as minor relatives of mast cells. However, recent studies have illustrated non-redundant roles for basophils in various immune responses, including allergic reactions and protective immunity against parasites. We previously demonstrated that basophils but not mast cells play an important role in the development of IgE-mediated, delayed-onset allergic inflammation in the skin, designated IgE-CAI. However, it remains elusive how basophils trigger the skin inflammation. In this study, we focused on mast cell protease 11 (mMCP-11) that shows a tryptase activity, and is expressed by basophils rather than mast cells. In order to elucidate the role for mMCP-11 in IgE-CAI, we generated engineered mice deficient for mMCP-11, in that the number of basophils was comparable to that in wild-type mice. Their basophils expressed normal levels of other proteases including mMCP-8 and surface FcεRI, and normally degranulated upon stimulation with IgE plus antigens, as judged by β-hexosaminidase release assay. Of note, skin swelling elicited by the IgE-CAI reaction was reduced in mMCP-11-deficient mice to half of that in wild-type mice. Moreover, the number of proinflammatory cells accumulating skin lesions, including eosinophils and neutrophils, was significantly reduced in mMCP-11-deficient mice. Thus, mMCP-11 released by basophils is a key effector molecule in the development of IgE-CAI. Keywords: basophil, mMCP-11, allergic inflammation, IgE, Tryptases Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Adaptive Immunity Citation: DEKI H, KAWANO Y, YOSHIKAWA S, EGAWA M, IKI M and KARASUYAMA H (2013). Basophil-derived mouse mast cell protease 11 is involved in the development of IgE-mediated chronic allergic inflammation. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00356 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Prof. Hajime KARASUYAMA, Tokyo Medical and Dental University, Tokyo, Japan, karasuyama.mbch@tmd.ac.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Hayato DEKI Yohei KAWANO Soichro YOSHIKAWA Mayumi EGAWA Misako IKI Hajime KARASUYAMA Google Hayato DEKI Yohei KAWANO Soichro YOSHIKAWA Mayumi EGAWA Misako IKI Hajime KARASUYAMA Google Scholar Hayato DEKI Yohei KAWANO Soichro YOSHIKAWA Mayumi EGAWA Misako IKI Hajime KARASUYAMA PubMed Hayato DEKI Yohei KAWANO Soichro YOSHIKAWA Mayumi EGAWA Misako IKI Hajime KARASUYAMA Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Critical role of P1-Runx1 in mouse basophil development

AbstractRunx1P1N/P1N mice are deficient in the transcription factor distal promoter-derived Runt-related transcription factor 1 (P1-Runx1) and have a > 90% reduction in the numbers of basophils in the BM, spleen, and blood. In contrast, Runx1P1N/P1N mice have normal numbers of the other granulocytes (neutrophils and eosinophils). Although basophils and mast cells share some common features, Runx1P1N/P1N mice have normal numbers of mast cells in multiple tissues. Runx1P1N/P1N mice fail to develop a basophil-dependent reaction, IgE-mediated chronic allergic inflammation of the skin, but respond normally when tested for IgE- and mast cell–dependent passive cutaneous anaphylaxis in vivo or IgE-dependent mast cell degranulation in vitro. These results demonstrate that Runx1P1N/P1N mice exhibit markedly impaired function of basophils, but not mast cells. Infection with the parasite Strongyloides venezuelensis and injections of IL-3, each of which induces marked basophilia in wild-type mice, also induce modest expansions of the very small populations of basophils in Runx1P1N/P1N mice. Finally, Runx1P1N/P1N mice have normal numbers of the granulocyte progenitor cells, SN-Flk2+/−, which can give rise to all granulocytes, but exhibit a > 95% reduction in basophil progenitors. The results of the present study suggest that P1-Runx1 is critical for a stage of basophil development between SN-Flk2+/− cells and basophil progenitors.

Role of Mast Cells and Basophils in IgE Responses and in Allergic Airway Hyperresponsiveness

We established a diphtheria toxin (DT)-based conditional deletion system using Il4 enhancer elements previously shown to be specific for IL-4 production in mast cells (MCs) or basophils (Mas-TRECK and Bas-TRECK mice). DT treatment of Bas-TRECK mice resulted in specific deletion of basophils, whereas both MCs and basophils were deleted in Mas-TRECK mice. DT-treated Mas-TRECK mice had impaired passive cutaneous anaphylaxis, IgE-mediated passive systemic anaphylaxis, and IgE-mediated chronic allergic inflammation, whereas DT-treated Bas-TRECK mice had impaired IgE-mediated chronic allergic inflammation. Using these mice, we also sought to tease out the role of MCs and basophils in airway hyperresponsiveness (AHR). Although MC deletion resulted in a slight increase in basal Ag-specific IgE levels and significant increases in basal IgE levels, we found that this deletion markedly impaired the AHR effector phase and was accompanied by decreased histamine levels. By contrast, basophil deletion had no effect on the AHR effector phase or on IgE production induced by systemic OVA immunization. Our results, using these newly established Mas-TRECK and Bas-TRECK models, demonstrated an indispensable role for MCs as effector cells in AHR.

IgE-mediated Chronic Allergic Inflammation (IgE-CAI)

This system is one of a chronic allergic inflammation model. A single subcutaneous injection of antigens elicits a delayed-type response manifested by ear swelling. The entire response consists of three phases: Immediate, late, and chronic. The early-phase swelling peak within 1 h after allergen challenge is followed by the late-phase swelling 6-10 h late. Importantly, the ear swelling at the late-phase started on day2 and peak on day4. This late-phase ear swelling response is defined as IgE-mediated chronic allergic inflammation (IgE-CAI) and mainly regulated by basophils.

Basophils play an important role in the resolution of inflammation by inducing alternative activation of macrophages through Th2 cytokine release (80.4)

Abstract Basophils have long been thought to be an initiator or effector of allergic inflammation. Here we report that basophils can function as a terminator of inflammation in IgE-mediated chronic allergic inflammation. In this allergy model, mice were passively sensitized with hapten TNP-specific IgE and then challenged with subcutaneous injection of TNP-OVA in the ear. The allergen challenge induced not only immediate-type ear swelling (mast cell-dependent) but also delayed-onset ear swelling (basophil-dependent). Analyses with flow cytometry and RT-PCR revealed that alternatively activated macrophages (AAMs) appeared in the skin lesions as the inflammation proceeded. The AAMs were induced in T cell-deficient but not IL-4/IL-13-deficient mice, indicating that AAM-inducing Th2 cytokines were produced by non-T cells. Basophil depletion abolished the development of AAMs. The cell transfer experiment revealed that basophil-derived IL-4 was essential for the alternative activation of macrophages. Depletion or developmental block of AAMs resulted in deterioration and prolongation of inflammation with massive accumulation of inflammatory cells. Taken together, basophils induce alternative activation of macrophages through Th2 cytokine release, leading to the resolution of inflammation.

Basophils are essential initiators of a novel type of chronic allergic inflammation

AbstractBasophils represent less than 1% of peripheral blood leukocytes and have often been considered as minor and possibly redundant circulating mast cells. The recent finding that basophils readily generate large quantities of T helper 2 (Th2) cytokines such as IL-4 provided new insights into the possible role of basophils in allergic disorders and immunity to pathogens. However, in-depth studies on basophils, particularly their functions in vivo, have been hampered by the lack of appropriate animal models, such as mutant animals deficient only in basophils. Here, we established a mAb that reacted with mouse basophils and depleted them when administered in vivo. The mAb treatment of mice did not show any significant effect on classical allergic reactions such as passive cutaneous anaphylaxis and contact hypersensitivity. In contrast, it completely abolished the development of IgE-mediated chronic allergic dermatitis that is characterized by massive eosinophil infiltration, even though basophils accounted for only approximately 2% of the infiltrates. The treatment during the progression of the dermatitis resulted in drastic reduction in numbers of infiltrating eosinophils and neutrophils, concomitantly with elimination of basophils from the skin lesions. Thus, basophils play a pivotal role in the development of IgE-mediated chronic allergic inflammation, as an initiator rather than as an effector.

Basophils function as initiators rather than effectors in IgE-mediated chronic allergic inflammation, independently of T cells and mast cells (38.6)

Abstract Basophils have often been considered as minor and possibly redundant “circulating mast cells”. We recently demonstrated that basophils play a pivotal role in the development of IgE-mediated chronic allergic inflammation (IgE-CAI), independently of T cells and mast cells. A single subcutaneous injection of multivalent antigens elicited not only immediate- and late-phase ear swelling but also delayed-onset ear swelling with massive eosinophil infiltration in mice sensitized with antigen-specific IgE. Here, we show that basophils function as initiators of the recruitment of eosinophils and neutrophils rather than effectors of inflammation in IgE-CAI. Even though basophils accounted for only 1–2% of the infiltrating cells in the skin legions, treatment of the IgE-sensitized mice with a newly-developed basophil-depleting mAb during the progression of IgE-CAI resulted in suppression of delayed-onset ear swelling with drastic reduction in numbers of not only basophils but also eosinophils and neutrophils infiltrating in the skin legions. Upon activation with IgE and corresponding antigens in vitro, basophils secreted soluble factors that stimulated skin adherent cells to produce soluble factors capable of attracting eosinophils and neutrophils. These findings indicate a novel mechanism of development of chronic allergic inflammation that is initiated and amplified by basophils.

Basophils Play a Critical Role in the Development of IgE-Mediated Chronic Allergic Inflammation Independently of T Cells and Mast Cells

The recruitment of basophils into the sites of allergic inflammation is often observed. However, no definitive evidence has been provided that basophils are crucially involved in the pathogenesis of chronic allergic disorders. Here, we show that basophils are responsible for the development of IgE-mediated chronic allergic inflammation independently of T cells and mast cells. A single subcutaneous injection of multivalent antigens elicited not only immediate- and late-phase ear swelling but also delayed-onset ear swelling with massive eosinophil infiltration in mice sensitized with antigen-specific IgE. Mast cells were essential for the immediate- and late-phase ear swelling but dispensable for the delayed one. T cells were also dispensable for the latter. Transfer of FcRI-expressing basophils into FcRI-deficient mice restored the development of the delayed-onset allergic inflammation. These findings indicate a novel mechanism of development of chronic allergic inflammation that is induced by basophils through the interaction of antigen, IgE, and FcRI.