title: Identification of a B cell differentiation factor(s) spontaneously produced by proliferating T cells in murine lupus strains of the lpr/lpr genotype.
abstract: Lymph node and spleen cells of the autoimmune MRL/Mp-lpr/lpr mouse strain spontaneously produce (in the absence of mitogenic stimulation) a factor(s) that induces B cell differentiation. This factor is not produced by the congenic MRL/n mouse strain that lacks the lpr gene or by normal mouse strains. However, lymphoid cells of the B6-lpr/lpr (B6/1) strain also produce a B cell differentiation factor. Although the factor acts on resting B cells, its effect is greatly magnified by activating the B cells with anti-mu or lipopolysaccharide. MRL/l mice begin producing the factor as early as 1 mo of age but levels increase with age and appearance of lymphoproliferation. Cell depletion studies reveal that this factor is produced by T cells of the Lyt-1+2-phenotype. Because of its association with the lpr/lpr genotype, we term this B cell differentiation factor L-BCDF. Functional analysis of L-BCDF reveals that it acts regardless of cell density in culture and in the absence of interleukin 2 (IL-2). In fact, the increase in the production of L-BCDF by MRL/1 T cells with aging occurs concomitantly with a marked decrease in their ability to produce IL-2. No T cell replacing factor activity or B cell growth factor-like activity can be detected in MRL/l-derived supernatants. L-BCDF induces both IgM and IgG synthesis in lipopolysaccharide-activated B cells; however, it has a greater effect on IgG secretion. In particular, the production of IgG1, IgG2a, and IgG2b are markedly enhanced in the presence of L-BCDF. The spontaneous production of L-BCDF by T cells of SLE mice of lpr/lpr genotype suggests an association of this factor with autoimmunity.
mesh_terms: D000375:Aging; D000818:Animals; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D005838:Genotype; D006133:Growth Substances / Q000096:biosynthesis* / Q000494:pharmacology; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4; D008180:Lupus Erythematosus, Systemic / Q000235:genetics / Q000276:immunology*; D008213:Lymphocyte Activation; D008222:Lymphokines; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006133:Growth Substances; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007376:Interleukin-2; D008222:Lymphokines; C021649:concanavalin A-induced helper factors; D003208:Concanavalin A; D015847:Interleukin-4