The Nature of Antibodies Synthesized during the Immune Response to Leptospira Biflexa

Abstract

Summary Agglutinating and hemolytic antibodies to Leptospira biflexa were examined after injection of rabbits with increasing concentrations of the spirochete. The magnitude of the agglutinating antibody response was dependent upon the antigen concentration. The response to the hemolytic antigen was not increased with increasing antigen but a persistent synthesis or renewed synthesis was observed which appeared to be quantitatively related to the level of antigen injected. Secondary responses were initiated with a low dose of antigen. The agglutinating antibody response was similar to the primary response with that same dose of antigen. Hemolytic antibody synthesis, however, was increased more than twelvefold over the primary response. This quantitative difference in the secondary response of the agglutinating and hemolytic antibodies might be explained on the basis of previous findings that anamnestic type responses are usually associated with the synthesis of low molecular weight antibody (7 S) but not heavy antibodies (19 S). However, examination of primary and secondary response antisera by density gradient ultracentrifugation and sensitivity to reduction indicate that both the agglutinating and hemolytic antibodies are rapidly sedimenting and sensitive to reduction throughout the immune response. Apparently anamnesis can be associated with macroglobulin antibody synthesis to certain antigens.