title: Cellular basis of in vitro anti-DNA antibody production: evidence for T cell dependence of IgG-class anti-DNA antibody synthesis in the (NZB X NZW)F1 hybrid.
abstract: An in vitro system was designed to measure anti-DNA antibody synthesis, and the cellular basis of this autoantibody production in NZB X NZW (B/W)F1 (B/W F1) mice was analyzed. The spleen cells from old B/W F1 mice contained a number of B cells that spontaneously produced anti-DNA antibodies of both IgM and IgG classes in the absence of stimulants, thereby demonstrating that these B cells had been activated in vivo. These activated B cells could be removed by Sephadex G-10 column (G-10) filtration. Such G-10-passed, homogeneously small B cells were activated by the stimulant lipopolysaccharide (LPS) and produced both IgM and IgG class anti-DNA antibodies. The G-10-passed cells contained both B and T cells, and the cytotoxic treatment of the cells with monoclonal antibodies to T cells, anti-Thy-1 and anti-L3T4, abolished the LPS-induced IgG class, but not IgM class, anti-DNA antibody syntheses. Thus, the LPS-induced production of IgG class anti-DNA antibodies in B/W F1 mice is regulated by T cells. Reconstitution experiments revealed the requirement of T-B cell contact but not of the proliferative response of T cells. Moreover, there was no apparent adherent cell requirement. Such IgG class anti-DNA antibodies were produced only by spleen cells from old B/W F1 mice, but not from young B/W F1, NZB, NZW, and C57BL/6 mice. Like IgM class anti-DNA antibodies, LPS-induced synthesis of polyclonal IgM was T cell-independent. Only a slight reduction in the polyclonal IgG synthesis was observed after the G-10-passed cells had been treated with anti-Thy-1 antibody plus complement. This study should facilitate investigation of cell to cell interactions in the formation of autoantibodies and their correlations to immunologic abnormalities in autoimmune disease.
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000096:biosynthesis* / Q000145:classification; D001327:Autoimmune Diseases / Q000276:immunology; D002469:Cell Separation; D002850:Chromatography, Gel; D003433:Crosses, Genetic; D004247:DNA / Q000276:immunology*; D005260:Female; D007074:Immunoglobulin G / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008814:Mice, Inbred NZB; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
chemical_list: D000974:Antibodies, Antinuclear; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D004247:DNA