title: VH gene analysis of spontaneously activated B cells in adult MRL-lpr/lpr mice. J558 bias is not limited to classic lupus autoantibodies.
abstract: To determine the genetic origins of lupus auto-antibodies, we analyzed the relationship between VH gene usage and auto-Ag-binding properties of 352 B cell hybridomas derived from MRL-lpr/lpr mice. The hybridomas were derived from neonatal, 1-month-old, 3-month-old, and 6-month-old mice. The experimental strategy provided that the hybridomas were monoclonal at initial evaluation, so the Ag binding and V gene frequencies of the entire population could be determined. Initially, 1032 Ig-producing hybridomas were evaluated for binding to six Ag; VH gene family use was determined in 119 anti-DNA and anti-rabbit thymus extract (RTE) antibodies (autoantibodies) and in 233 age-matched Ig that did not bind to any of the six Ag (nonbinders). Neonatal B cells, including cross-reactive IgM autoantibodies and nonbinder IgM, used relatively 3' VH genes. The majority of B cells in adult mice used VH genes of the J558 family. Although J558 use was significantly higher among the autoantibodies (anti-DNA and anti-RTE) than among the nonbinder Ig, this difference was due to a higher frequency of J558 use by 1-month-old mice. At 3 months, J558 use by the nonbinder Ig increased to the same frequency of J558 use as in the autoantibody population. J558 use in both groups of antibodies exceeded a previously reported estimation of J558 expression in the functional B cell repertoire of young adult MRL-lpr/lpr mice. Several subgroups of antibodies that share properties with pathogenic Ig, including IgG, cross-reactive Ig, and anti-dsDNA autoantibodies, demonstrated a marked preferential expression of the J558 family. These results suggest that there is an age-related bias in the activation of B cells using J558 VH genes in MRL-lpr/lpr mice that is under the influence of a selective force distinct from, or in addition to, an ssDNA or RTE auto-Ag-driven response.
authors.affiliation: Department of Medicine, University of Pennsylvania, Philadelphia 19104.
authors.forename: M H
authors.initials: MH
authors.lastname: Foster
authors.forename: M
authors.initials: M
authors.lastname: MacDonald
authors.forename: K J
authors.initials: KJ
authors.lastname: Barrett
authors.forename: M P
authors.initials: MP
authors.lastname: Madaio
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000235:genetics; D001323:Autoantibodies / Q000235:genetics*; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D005803:Genes, Immunoglobulin; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007132:Immunoglobulin Isotypes / Q000032:analysis; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D011817:Rabbits; D013950:Thymus Gland / Q000276:immunology
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D007143:Immunoglobulin Heavy Chains; D007132:Immunoglobulin Isotypes; D007135:Immunoglobulin Variable Region