title: Enhanced IgA class switching in marginal zone and B1 B cells relative to follicular/B2 B cells.
abstract: Mouse splenic marginal zone (MZ) B cells and B1 B cells enriched in the peritoneal cavity respond preferentially to T cell-independent Ags compared with follicular (FO)/B2 B cells. Despite the differential responses of B cell subsets to various stimuli, and despite the need for multiple stimuli to induce IgA class switching, the relative contribution of B cell subpopulations to IgA production is unknown. By culturing purified B cell populations, we find that MZ and peritoneal B1 cells switch more readily to IgA than do splenic FO or peritoneal B2 cells in BLyS/LPS/TGF-beta. Addition of IL-4, IL-5, and anti-IgD dextran to the cultures enhances IgA switching in FO/B2 and MZ B cells to a similar frequency, but this treatment suppresses IgA class switching in B1 cells. Thus, IgA switching differs among purified B cell subsets, suggesting that individual B cell populations could contribute differentially to IgA expression in vivo, depending on available stimuli.
authors.affiliation: Immunology and Virology Program, Department of Molecular Genetics and Microbiology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
authors.forename: Denise A
authors.initials: DA
authors.lastname: Kaminski
authors.forename: Janet
authors.initials: J
authors.lastname: Stavnezer
mesh_terms: D000818:Animals; D016175:B-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D002478:Cells, Cultured; D003911:Dextrans / Q000494:pharmacology; D007070:Immunoglobulin A / Q000096:biosynthesis* / Q000235:genetics; D017578:Immunoglobulin Class Switching; D015847:Interleukin-4 / Q000494:pharmacology; D015848:Interleukin-5 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D010537:Peritoneum / Q000166:cytology / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: D003911:Dextrans; D007070:Immunoglobulin A; D015848:Interleukin-5; D008070:Lipopolysaccharides; D016212:Transforming Growth Factor beta; D015847:Interleukin-4