Production of streptococcal M-typing antisera. I. Antigenic response in different breeds of rabbits.

M-antigens of seven M-types of group A streptococci were used to compare antigenic response in six breeds of rabbits: New Zealand White, New Zealand Red, Dutch, Googy, California, and Palomino. No appreciable differences among breeds were demonstrated. M-types used for immunization varied considerably in their ability to evoke a response of an antibody which met rigid criteria for streptococcal M-typing antisera. The importance of the injection and bleeding schedule and absorption conditions for preparing type-specific absorbed antisera were demonstrated. Evaluating and processing sera from individual animals at an optimal time rather than using pooled sera enhanced the possibilities for preparing satisfactory type-specific antisera.