Interaction between anti-DNA and anti-DNA-binding protein autoantibodies in cryoglobulins from sera of patients with systemic lupus erythematosus.
We have previously shown that sera from some patients with SLE and related disorders contain autoantibodies to a DNA-binding protein complex designated p70/p80. The present study shows that anti-p70/p80 autoantibodies are frequently accompanied by anti-DNA antibodies and cryoglobulins. When the cryoglobulins were isolated, they were found to be specifically enriched in both anti-p70/p80 and anti-DNA activities. The anti-p70/p80 and anti-DNA antibodies were found to be distinct populations of autoantibodies rather than a single crossreactive species, since they could be separated from one another by chromatography on DNA-cellulose. Certain human anti-DNA mAbs could inhibit the binding of autoimmune polyclonal anti-p70/p80 antibodies to p70/p80, suggesting that anti-DNA antibodies might also associate with the variable regions of some anti-p70/p80 antibodies in the cryoglobulins. Binding of one murine anti-p70/p80 mAb (111-12) also was inhibited by certain human anti-DNA mAbs, but the binding of another murine mAb (162-11) to a different epitope of p70/p80 was not. These studies suggest that certain anti-DNA antibodies may interact with the variable regions of a population of anti-p70/p80 antibodies. The cryoglobulins found in the sera containing both anti-p70/p80 and anti-DNA antibodies may represent immune complexes consisting, in part, of idiotype and antiidiotype.
D000974:Antibodies, Antinuclear / Q000032:analysis; D000911:Antibodies, Monoclonal / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis / Q000276:immunology*; D003450:Cryoglobulins / Q000276:immunology* / Q000302:isolation & purification; D004247:DNA / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000276:immunology*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008947:Mixed Connective Tissue Disease / Q000276:immunology
D000974:Antibodies, Antinuclear; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001323:Autoantibodies; D003450:Cryoglobulins; D004268:DNA-Binding Proteins; D004247:DNA