title: IgG1 and IgG2a production by autoimmune B cells treated in vitro with IL-4 and IFN-gamma.
abstract: Autoimmune MRL-lpr/lpr and NZB/W mice spontaneously secrete large quantities of pathogenic IgG1 and IgG2a autoantibodies. NZB mice also produce autoantibodies but these tend to be of the IgM H chain class. This work examines whether differences in the isotype of autoantibody produced by lupus-prone mice reflects differences in the sensitivity of autoreactive B cells to lymphokine-mediated IgG secretion. Twenty-five percent of normal BALB/c B cells produced IgG1 when stimulated in vitro with IL-4 plus LPS. This was comparable with the effect of IL-4 on small resting B cells from MRL-lpr/lpr and NZB/W mice. In contrast, less than 8% of the resting B cells from NZB mice produced IgG1 under these conditions. LPS plus IFN-gamma induced 5% of BALB/c and NZB/W but only 1% of NZB B cells to secrete IgG2a. Because lymphocytes from both young and old NZB mice showed diminished IgG1 and IgG2a secretion after lymphokine treatment, B cells from this strain appeared to be intrinsically resistant to the effects of IL-4 and IFN-gamma. In contrast, a disproportionately large proportion (22%) of B cells from adult MRL-lpr/lpr mice produced IgG2a when treated with IFN-gamma in vitro. Only B cells from MRL-lpr/lpr mice with active disease responded with such high levels of IgG2a production: cells from animals that had not yet developed clinical disease produced normal levels of IgG2a. Within each strain, B cells producing antibodies against autoantigens such as DNA, bromelain-treated mouse RBC and Sm responded to treatment with IL-4 and IFN-gamma in a manner indistinguishable from B cells producing antibodies against conventional Ag such as TNP and ARS.
authors.affiliation: Center for Biologics Research and Evaluation, Food and Drug Administration, Bethesda, MD 20892.
authors.forename: D M
authors.initials: DM
authors.lastname: Klinman
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D000921:Antibody-Producing Cells / Q000276:immunology*; D001323:Autoantibodies / Q000096:biosynthesis; D001324:Autoantigens / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007132:Immunoglobulin Isotypes / Q000096:biosynthesis; D007371:Interferon-gamma / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains; D011994:Recombinant Proteins
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D011994:Recombinant Proteins; D015847:Interleukin-4; D007371:Interferon-gamma