Antibody Responses of Monkeys and Rabbits to Streptokinase and Staphylokinase.

In our previous experiments, because of the weakness of antigenicity of streptokinase (STK) and staphylokinase (SAK), the antibody response of rabbits and dogs to these extracellular bacterial substances could not be demonstrated by the measurement of antibody titers in the sera of the immunized animals, although the antibody response of humans to STK was proved by demonstrating the rise of anti-STK titers in the sera of human volunteers treated therapeutically with a commercial STK-preparation (Varidase-Lederle). In our present experiments, however, the antigenicity of these substances was clearly demonstrated by the used of monkeys as the experimental animals, in substitution for rabbits, or by the improvement of the immunizing method in rabbits. In the experiments with monkeys anti-STK and anti-SAK were readily produced in the sera of the immunized animals by the primary injections of STK and SAK respectively without adjuvant. In the case of a primary immunization of rabbits, however, the addition of complete Freund's adjuvant to STK or SAK was necessary for the production of anti-STK or anti-SAK in the sera of the immunized animals. Considerablly high titers of anti-STK or anti-SAK were detected in the sera of rabbits, receiving a booster injection after a long lapse of time following the primary injection of the same antigens. The difference between the antibody response of monkeys and that of rabbits to STK and SAK was discussed in connection with natural infection of streptococci and staphylococci among these animal species.