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Flipped Classroom Session
Micro 204 Flipped Classroom Session Antibodies IgE and IgA Chris Allen Tony DeFranco
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IgE Antibody Function Parasitic worm mediators including histamine
chemokines cytokines IgE FceRI inflammation mast cell or basophil
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Normal Functions of Antibodies
Neutralization toxins viruses Parasitic worm IgA inflammation IgG Mast cell IgE Macrophage bacteria Opsonization Toxic granules Foreign/ infected cell Antibody-dependent cytotoxicity bacteria Complement activation IgM IgG IgG
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Differences in Fc Receptors
bacteria IgG IgE Mast Cell FceRI Macrophage FcgR
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Changes in Antibodies Class switch recombination IgG IgM IgE IgD IgE
Variable region (antigen-binding) IgG IgE IgM IgD IgA Constant region (function) IgE AID Affinity maturation mutation, selection Low affinity High Membrane vs secreted Transmembrane & Intracellular Domains B cell Plasma cell
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B Cell Differentiation Pathways
Memory B Cell Short-Lived Plasma Cell Germinal Center Long-Lived Plasma Cell Activated B Cell Affinity Maturation Hypermutation, Selection
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Germinal Center Selection
Antigen Apoptosis BCR signal Proliferation highest affinity Differentiation Memory B Cell T cell T cell help GC B Cells highest affinity Plasma Cell
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Helminth parasite model: Nippostrongylus brasiliensis infection
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Differences in Kinetics of Antibody Responses
Infection N. brasiliensis L3 larvae Erazo A. et al. Immunity 2007, 26: Cheng L.E. et al. J Immunol 2010, 185:
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Differences in IgG1 vs IgE Germinal Center B Cell Responses
N. brasiliensis infection Differences in IgG1 vs IgE Germinal Center B Cell Responses IgG1+ Germinal Center B Cells IgE+ Germinal Center B Cells Yang Z. et al. Immunity 2012, 36: Similar data in: Talay O. et al. Nat Immunol 2012, 13: He J.S. et al. J Exp Med 2013, 210:
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Questions Why do IgE+ B cells disappear from the germinal center?
What are the implications for the IgE antibody response?
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Why IgE B cell lifespan and affinity may be limited
Neutralization toxins viruses Parasitic worm inflammation Mast cell IgG IgA IgE Systemic IgE activation
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