Identification of autoanti-Thi-1 antibody in the sera of BALB/c mice immune to P1798 lymphoma.

The specificity was established for the anti-thymocyte autoantibody which appeared in BALB/c mice (BAA) during immunization to the P 1798 lymphoma. The results indicate that BAA is specific for the Thy-1 alloantigen of murine T cells. By immunoprecipitation of 125I-labeled A/J thymocyte surface antigens from freeze-thaw lysates and electrophoretic resolution of the immunoprecipitates on sodium dodecyl sulfate polyacrylamide gels, the BAA and congenic anti-Thy-1.1 or 1.2 were shown to be specific for determinants on the same antigens. Specificity of BAA for Thy-1.2 was shown also quantitative absorption studies. Coating P 1798 lymphoma cells with either BAA or anti-Thy-1.2 reduced the absorptive capacity of these cells for the same or the reciprocal antiserum. Coating P 1798 with an antiserum to P 1798 which was indifferent to the Thy-1.2 alloantigen did not diminish the absorptive capacity of these cells for either BAA or anti-Thy-1.2. These studies have provided firm evidence that BAA is specific for determinants on the Thy-1 alloantigen.