Rapid loss of IgM expression by normal murine B cells undergoing IgG1 and IgE class switching after in vivo immunization.
Injection of mice with polyclonal goat anti-mouse IgD antibody (G alpha M delta) stimulates a potent T cell-dependent immune response characterized by large increases in serum IgG1 and IgE concentrations and by the generation of substantial numbers of membrane (m)IgG1+ B cells. The onset of this response occurs 6 days after G alpha M delta injection and peaks by day 7 to 8. Utilizing two color fluorescence analysis and cell sorting we demonstrate that most mIgG1-expressing B cells lack mIgM during the period of onset of Ig isotype switching (day 6). Both IgG1 and IgE are produced predominantly by mIgM- cells. On day 6, IgG1 and IgE are secreted predominantly by cells expressing mIgG1 and mIgE, respectively. By day 8, a majority of the IgG1 secretion occurs among the mIgG1- cells but virtually all IgE secretion continues to come from the mIgE+ population. B cells that strongly express mIgG1 secrete little IgM or IgE. Freshly harvested B cells expressing mIgG1, 6 days after G alpha M delta injection, have undergone substantial deletion of CH mu-specific DNA in contrast to their mIgG1- counterparts. Hence, the great majority of B cells that switch to the IgG1 or IgE isotypes in vivo rapidly lose their expression of IgM.
Snapper
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CM
Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.
Finkelman
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D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D004247:DNA / Q000032:analysis; D005260:Female; D006041:Goats; D007114:Immunization; D007073:Immunoglobulin E / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis*; D007132:Immunoglobulin Isotypes / Q000032:analysis* / Q000378:metabolism; D007075:Immunoglobulin M / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D011961:Receptors, Fc / Q000276:immunology; D017455:Receptors, IgE
D000888:Antibodies, Anti-Idiotypic; D000944:Antigens, Differentiation, B-Lymphocyte; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; D011961:Receptors, Fc; D017455:Receptors, IgE; D007073:Immunoglobulin E; D004247:DNA