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Conroy, Michelle

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Conroy

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Michelle

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Conroy, Michelle

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  • Publication
    Sialylation of Immunoglobulin E Is a Determinant of Allergic Pathogenicity
    (Springer Science and Business Media LLC, 2020-05-20) Shade, Kai-Ting; Conroy, Michelle; Washburn, Nathaniel; Kitaoka, Maya; Huynh, Daniel; Laprise, Emma; Patil, Sarita U.; Shreffler, Wayne; Anthony, Robert M.; Anthony, R
    Approximately one-third of the world’s population suffers from allergies1. Allergen exposure crosslinks mast cell- and basophil-bound immunoglobulin E (IgE), triggering the release of inflammatory mediators, including histamine2. Although IgE is absolutely required for allergies, it is not understood why total and allergen-specific IgE concentrations do not reproducibly correlate with allergic disease3-5. It is well-established that glycosylation of IgG dictates its effector function and has disease-specific patterns. However, whether IgE glycans differ in disease states or impact biological activity is completely unknown6. We therefore unbiasedly examined glycosylation patterns of total IgE from peanut-allergic and non-atopic individuals. This revealed an increase in sialic acid content on total IgE from peanut-allergic individuals compared to non-atopic subjects. Sialic acid removal from IgE attenuated effector cell degranulation and anaphylaxis in multiple functional models of allergic disease. Therapeutic interventions, including sialic acid removal from cell-bound IgE with a FcεRI targeted-neuraminidase, or administration of asialylated IgE, markedly reduced anaphylaxis. Together, these results establish IgE glycosylation, and specifically sialylation, as an important regulator of allergic disease.
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    Publication
    A single glycan on IgE is indispensable for initiation of anaphylaxis
    (The Rockefeller University Press, 2015) Shade, Kai-Ting C.; Platzer, Barbara; Washburn, Nathaniel; Mani, Vinidhra; Bartsch, Yannic C.; Conroy, Michelle; Pagan, Jose D.; Bosques, Carlos; Mempel, Thorsten; Fiebiger, Edda; Anthony, Robert
    Immunoglobulin ε (IgE) antibodies are the primary mediators of allergic diseases, which affect more than 1 in 10 individuals worldwide. IgE specific for innocuous environmental antigens, or allergens, binds and sensitizes tissue-resident mast cells expressing the high-affinity IgE receptor, FcεRI. Subsequent allergen exposure cross-links mast cell–bound IgE, resulting in the release of inflammatory mediators and initiation of the allergic cascade. It is well established that precise glycosylation patterns exert profound effects on the biological activity of IgG. However, the contribution of glycosylation to IgE biology is less clear. Here, we demonstrate an absolute requirement for IgE glycosylation in allergic reactions. The obligatory glycan was mapped to a single N-linked oligomannose structure in the constant domain 3 (Cε3) of IgE, at asparagine-394 (N394) in human IgE and N384 in mouse. Genetic disruption of the site or enzymatic removal of the oligomannose glycan altered IgE secondary structure and abrogated IgE binding to FcεRI, rendering IgE incapable of eliciting mast cell degranulation, thereby preventing anaphylaxis. These results underscore an unappreciated and essential requirement of glycosylation in IgE biology.