DIFFERENCES IN IMMUNIZATION AND SENSITIZATION IN RABBITS INJECTED WITH RELATIVELY AVIRULENT OR HIGHLY VIRULENT CULTURES OF THE SAME STRAIN (H) OF HEMOLYTIC STREPTOCOCCUS

Open Access
Publisher Website
Google Scholar
Abstract
A group of rabbits was injd. intraderm. at intervals with small doses of a relatively avirulent hemolytic streptococcus. Another group received injs. of the same strain of streptococcus made highly virulent by intrapleural passage in rabbits. The lesions produced were observed and measured. Tests for agglutinins and precipitins were also made. The degree of skin hypersensitiveness was determined with streptococcus filtrate. The relatively avirulent strain produced a considerable amount of skin sensitivity to the filtrate, and there was scant demonstrable immunity as indicated by the size of the lesions. The organism in the highly virulent phase produced little sensitization and considerable immunity. Rabbits injd. with the virulent culture developed antibodies earlier and in larger amounts than animals injd. with the avirulent form of the same organism. These studies indicate that an increase in virulence of hemolytic streptococci enhances the ability to protect against local infection and increases antibody formation but diminishes the production of sensitization.