Experimental erythrocyte autoimmunity I. MICE CONGENIC FOR IMMUNOGLOBULIN ALLOTYPES VARY IN PRODUCTION OF AUTOANTIBODIES BUT PRODUCE SUPPRESSOR CELLS NOT RESTRICTED BY ALLOTYPES.

Erythrocyte autoantibodies can be elicited in mice by injections of rat RBC which are cross-reactive with mouse RBC. This report shows that reduction of autoantibodies is dependent, in part, on gene(s) outside the H-2 complex. Using CBA mice congenic for Ig allotype and the F₁ and F₂ hybrids, a higher incidence of autoantibody production was observed in mice bearing the Ig allotype 1^b (1^bb' or 1^ab) in contrast to mice homozygous for the allotype Ig-1^a. Serum haemagglutination titres against rat RBC were not reduced in the groups of mice with the lower incidence of autoantibody production. A probable explanation for these observations is that the change in Ig allotype is associated with some change in the variable region determining autoimmune specificity that is governed by V_H genes linked to allotype genes. The transfer of 30× 10⁶ spleen cells from Coombs' positive mice to syngeneic recipients before starting the immunization regime with rat RBC suppressed autoantibody production and enhanced antibody production against rat RBC. These suppressor cells were effective in congemic mice and in F₁ hybrids, which suggest that the Ig allotype is not a crucial site for the effector stage of suppression of this autoimmune response. [ABSTRACT FROM AUTHOR]