title: IgG subclass potential of surface IgM-negative and surface IgM-positive human peripheral blood B cells.
abstract: To examine the IgG subclass potential of B cells at various stages of maturation, human peripheral blood B cells were separated into surface IgM-positive (sIgM+) and surface IgM-negative (sIgM-) cells by panning techniques and cultured with pokeweed mitogen, LPS, or Epstein-Barr virus. At the end of 7 days, cells were harvested, counted, spun onto slides, fixed, and stained with subclass-specific monoclonal antibodies. In all experiments with all mitogens, there was an enrichment of IgG2 plasma cells in sIgM+ cultures compared to the sIgM- cultures (P less than 0.0001). In the Epstein-Barr virus-stimulated cultures there was also a statistically significant enrichment for IgG3 in the sIgM+ cultures (P less than 0.01). In contrast, sIgM- cultures were always enriched for IgG1 plasma cells (P less than 0.0001). In the pokeweed mitogen-stimulated cultures, the sIgM- cultures also contained a higher proportion of IgG4 plasma cells than did the sIgM+ cultures (P less than 0.01). These results demonstrate that the IgG subclass potential of immature, surface IgM-positive precursors of IgG plasma cells differs from that of more mature surface IgM-negative precursors.
mesh_terms: D001402:B-Lymphocytes / Q000145:classification / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D002478:Cells, Cultured; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007132:Immunoglobulin Isotypes / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000276:immunology*; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D011043:Pokeweed Mitogens; D011947:Receptors, Antigen, B-Cell