Antigenic properties of the type-specific substance derived from group a hemolytic streptococci

Abstract

1. A substance extracted from group A hemolytic streptococcus is described, which induces active immunity in mice, and in rabbits gives rise to precipitins and to protective antibodies passively transferable to mice. 2. The active immunity in mice is principally type-specific, but some degree of non-type-specific immunity is also developed. The passively transferable protective antibodies are type-specific with only a slight suggestion of non-type specificity. In the precipitin test, the rabbit immune sera give both type-specific and non-type-specific reactions which have not been fully analyzed serologicaUy. 3. Substances contained in the extract absorb the protective antibodies from the serum of rabbits immunized with whole hemolytic streptococci. © 1939, Rockefeller University Press., All rights reserved.