COMMON OCCURRENCE OF AN ANTIIDIOTYPIC ANTIBODY THAT RECOGNIZES T14-DNA ANTIBODIES IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS( ANTI)

Objective. To investigate whether antibodies to a T14 anti-DNA antibod y can be found in patients with systemic lupus erythematosus (SLE). Me thods. Seventy-six serum samples (37 from patients with SLE) were rand omly selected from among sera submitted for routine antinuclear antibo dy testing, Short, overlapping peptides based on the partial V-H (vari able region of the heavy chain) sequence of the T14 antibody were synt hesized on multipins and screened for reactivity with SLE sera, In add ition, selected peptides from T14 and related proteins were synthesize d in bulk and screened for reactivity with both SLE and control sera, A monoclonal antibody was generated to determine the prevalence of the T14 idiotype (T14 + Id) in the different study populations. Results. Antibodies were detected by a peptide based on the third complementari ty-determining region (CDR3) of the T14 protein in 15 (41%) of 37 pati ents with SLE or 15 (54%) of 28 who had anti-DNA antibodies, in 3 (9%) of 34 patients without anti-DNA antibodies (9 of whom had SLE), and i n 6 (10%) of 57 healthy controls, In SLE sera, the antiidiotypic (anti -Id) responses (IgM and IgG) correlated well with the anti-DNA respons es (IgG), and both responses correlated well with the T14+ Id activity in SLE sera. Control peptides based on the 18/2 (16/6+ Id) and S107 p roteins detected low antibody activities in SLE sera, attributable to cross-reactivity with the T14 peptide. A peptide based on an unrelated human antibody was not reactive with these sera. Conclusion, Anti-Id antibodies directed to T14 V(H)CDR3 were found commonly in the sera of patients with SLE, and they appeared to be induced by the anti-DNA an tibodies present in the sera, Based on these findings, these secondary antibodies may be pathogenic in SLE.