title: Regulation of differentiation in CD5+ and conventional B cells. Sensitivity to LPS-induced differentiation and interferon-gamma-mediated inhibition of differentiation.
abstract: We have analyzed the response of conventional and CD5+ B cells to the opposing signals delivered by LPS and interferon-gamma (IFN-gamma). Cultured CD5+ B cells secrete more IgM than conventional B cells in response to low concentrations of LPS. This increase in LPS-induced IgM production is due to an increased precursor frequency of IgM-secreting cells in CD5+ B cells. The IgM-secreting clones derived from conventional splenic B cells or CD5+ peritoneal B cells exhibit similar kinetics of IgM secretion in response to LPS, and the amount of IgM produced per B cell clone was not higher in CD5+ B cells. Thus, the CD5+ B cell compartment produces more IgM in response to LPS because of increased activation of precursors at any given concentration of LPS. IFN-gamma inhibits low-dose LPS-driven IgM secretion in both conventional and CD5+ B cells. IFN-gamma mediates inhibition of IgM secretion by decreasing the precursor frequency of IgM-secreting conventional or CD5+ B cells by threefold. IFN-gamma also decreases the anti-ssDNA precursor frequency of LPS-driven splenic B cells from autoimmune NZB mice. This study documents an important role for IFN-gamma in the regulation of polyclonal B cell activation and suggests that loss of IFN-gamma activity may permit or promote excessive B cell activation.
authors.affiliation: Department of Internal Medicine, University of Iowa College of Medicine, Iowa City.
authors.forename: J H
authors.initials: JH
authors.lastname: Chace
authors.forename: N S
authors.initials: NS
authors.lastname: Abed
authors.forename: G L
authors.initials: GL
authors.lastname: Adel
authors.forename: J S
authors.initials: JS
authors.lastname: Cowdery
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000096:biosynthesis; D015703:Antigens, CD / Q000378:metabolism*; D016175:B-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology; D018956:CD5 Antigens; D002454:Cell Differentiation / Q000187:drug effects; D004277:DNA, Single-Stranded / Q000276:immunology; D005260:Female; D007075:Immunoglobulin M / Q000378:metabolism; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008811:Mice, Inbred DBA; D008814:Mice, Inbred NZB
chemical_list: D000974:Antibodies, Antinuclear; D015703:Antigens, CD; D018956:CD5 Antigens; D004277:DNA, Single-Stranded; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D007371:Interferon-gamma