title: VH gene expression is restricted in anti-IgG antibodies from MRL autoimmune mice.
abstract: Antibodies directed against IgG and DNA are found in the sera of autoimmune MRL/Mp lpr/lpr mice. Little is known of the molecular mechanisms underlying expression of such autoantibodies. We have investigated the binding diversity and pattern of VH gene expression in a panel of murine anti-IgG antibodies. We constructed eight hybridoma clones secreting IgM antibodies that bound to mouse IgG by using spleen cells from MRL/Mp lpr/lpr mice varying in age from 4 to 15 wk; one clone was derived from a 32-wk-old MRL +/+ mouse. The monoclonal IgM products exhibited varying binding specificities for intact mouse IgG, fragments of mouse IgG [Fc, Fab, (Fab')2], and heterologous IgG. Two of these antibodies crossreacted with B and/or Z DNA. Probes from seven of eight identified mouse VH gene families (7183, S107, Q52, J558, J606, 36-60, and 3609) were hybridized under high-stringency conditions with cytoplasmic RNA blots from each clone. Six clones hybridized only with the probe from the five-member 36-60 family. The remaining three clones crosshybridized with the 36-60 probe and the probe from the 60 member J558 family, perhaps reflecting somatic mutation from the original germline VH gene resulting in recognition by a probe from another family, in addition to the probe from the original germline family. Our results indicate that spontaneous MRL lpr/lpr anti-IgG antibodies are encoded predominantly by the 36-60 VH gene family and imply a nonrandom selection of this VH gene family in the production of these antibodies.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001327:Autoimmune Diseases / Q000276:immunology*; D004247:DNA / Q000276:immunology; D005260:Female; D006825:Hybridomas / Q000276:immunology; D007074:Immunoglobulin G / Q000145:classification / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D051379:Mice; D009693:Nucleic Acid Hybridization; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D004247:DNA