Basophil activation through ASGM1 stimulation triggers PAF release and anaphylaxis‐like shock in mice

Abstract

Basophils have been shown to contribute to anaphylaxis through either an IgE-FcεRI-dependent pathway or an IgG-FcγR pathway. However, it remains largely unclear whether basophils can be activated to promote anaphylaxis via a non-FcR pathway as well. The glycolipid receptor ASGM1 (Asialoganglioside gangliotetraosylceramide), which has an exposed GalNAcβ1-4Gal moiety and serves as a receptor for pathogen associated molecular patterns such as flagellin, was recently found to be expressed on basophils. Here, we demonstrate that stimulation of basophils with anti-ASGM1 antibodies promotes platelet-activating factor (PAF) secretion in vitro and in vivo. Moreover, we found that ASGM1 stimulation triggers basophil-and PAF-dependent anaphylactic shock in pertussis toxin (PTX)-pretreated mice. Thus, ASGM1 has a crucial role in basophil activation and basophil-mediated anaphylaxis-like shock in mice, especially when the vascular permeability is increased by PTX treatment. Our findings describe a novel anaphylaxisassociated pathway that is antigen-, antibody-, and FcR-independent.Keywords: Anaphylaxis r ASGM1 r Basophil r PAF Additional supporting information may be found in the online version of this article at the publisher's web-site IntroductionAnaphylaxis is a serious life-threatening allergic reaction characterized by rapid onset and potentially fatal outcomes [1]. The major manifestations of anaphylaxis include bronchoconstriction, pulmonary hypertension, systemic hypotension, and vascular leakage. A classical IgE-and FcεRI-dependent pathway has long been recognized to be associated with anaphylaxis. Binding of Correspondence: Dr. Fang Zheng e-mail: zhengfangtj@hust.edu.cn antigens to IgE and high-affinity cross-linking with FcεRI trigger the release of histamines from mast cells, resulting in anaphylaxis. Recently, various human and animal studies have indicated that IgG-and FcγR-involving pathways also mediate anaphylaxis in an IgE-independent fashion [2][3][4]. IgG antibodies, FcγRIIIA and FcγRIV, macrophages and neutrophils, as well as plateletactivating factor (PAF) are the main players in IgG-induced passive and active systemic anaphylaxis, in which IgE antibodies, FcεRI, mast cells, and histamine play a minor role [5]. It has been reported that in the absence of a specific allergen and antibodies, treatment with two injections of the cytokine IL-33 can trigger a third pathway for anaphylaxis in mice [6]. Kojimawww.eji-journal.eu Eur. J. Immunol. 2014. 44: 2468-2477 Innate immunity 2469 et al. also reported that in mice the anti-CD200R3 antibody Ba91 induced systemic and local anaphylaxis via an IgE-and IgG1-independent pathway that involved CD200R3 receptor activation [7]. Currently, it is largely unclear whether and how non-FcR receptors activate immune cells and trigger anaphylaxis. Basophils represent less than 1% of peripheral blood leukocytes. They are thought to contribute to anaphylaxis by releasing histamine and PAF. It has long been recognized that antigen binding to IgE and high-affinity cross-linkin...

Penicillin causes non-allergic anaphylaxis by activating the contact system

“…Given that penicillin can provoke severe and life-threatening anaphylaxis clinically, we first evaluated whether penicillin could cause anaphylactic shock (detected as hypothermia) 7 , 24 . Mice were made more sensitive to penicillin-induced shock by pretreating propranolol or PTX, which does not induce shock by itself but can augment the susceptibility of shock via enhancing vascular permeability 25 – 27 , 32 . Penicillin contributed to obvious hypothermia in both propranolol- and PTX-pretreated mice (Fig.…”

“…The anaphylactic shock assay in PTX-pretreated mice was performed according to previously described procedures 27 . Briefly, the mice were injected (i.p.)…”