A common idiotype expressed on a murine anti-Sm monoclonal antibody and antibodies in SLE sera.
A rabbit anti-idiotypic antiserum made against a murine monoclonal anti-Sm autoantibody (Y2) was used in a solid-phase radioimmunoassay to investigate idiotypic cross-reactivity among anti-Sm antibodies present in sera from patients with systemic lupus erythematosus. Sera from 25 of 51 SLE patients (49%) containing anti-Sm antibodies were positive for this Y2 idiotype compared to only one of 22 normal human sera. Nine of 28 SLE patients (32%) whose sera were anti-Sm negative were also positive for the Y2 idiotype in low titre. Binding was not due to rheumatoid factor-like activity but was specific for the Y2 determinant and could be eliminated by absorption with Y2 monoclonal antibodies. The anti-idiotypic antibody blocked the ability of 12 of 25 anti-Sm positive lupus sera to bind Sm. Conversely, Sm antigen inhibited the binding of anti-idiotypic antibody in nine of 12 lupus sera.
Department of Medicine, University of Texas Health Science Center, Audie L. Murphy Memorial Veterans Administration Hospital, San Antonio 78284-7874.
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M
Takei
H
H
Dang
N
N
Talal
D000818:Animals; D000911:Antibodies, Monoclonal; D001323:Autoantibodies / Q000276:immunology; D001324:Autoantigens / Q000276:immunology*; D003429:Cross Reactions; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D007130:Immunoglobulin Idiotypes / Q000032:analysis*; D007132:Immunoglobulin Isotypes / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D051379:Mice; D017411:Ribonucleoproteins, Small Nuclear; D012859:Sjogren's Syndrome / Q000276:immunology; D013045:Species Specificity; D055517:snRNP Core Proteins
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001324:Autoantigens; D007106:Immune Sera; D007130:Immunoglobulin Idiotypes; D007132:Immunoglobulin Isotypes; D017411:Ribonucleoproteins, Small Nuclear; D055517:snRNP Core Proteins