Gel-Precipitation of Streptococcal Culture Supernates with Sera of Patients With Rheumatic Fever and Streptococcal Infection.

Abstract

Precipitin tests in semi-solid agar (gel-precipitin) were carried out between concentrates of streptococcal culture supernates and sera of various sources. Two techniques of diffusion in 1 dimension (tube) were used: the single-diffusion technique of Oudin, and a double-diffusion technique. Sera of rabbits previously injected with streptococcal culture supernates showed increasing numbers of bands as the course of injections progressed. Sera of such rabbits showed as many as 5 bands when tested with such concentrates, indicating that this was the minimum number of antigen-antibody systems present. Sera of patients with acute rheumatic fever and of patients convalescent from an acute streptococcal infection (scarlet fever) were also tested by this technique against concentrates of streptococcal culture supernates. The group with rheumatic fever showed a greater number of bands (a range of 2-7) than did the group with scarlet fever (0-4), when tested by the double-diffusion technique. The corresponding ranges found with the single-diffusion technique were 1-5 and 0-2, respectively. In a sampling of sera from convalescents from scarlet fever the number of bands was found to be no greater weeks alter the onset of the infection than 3 weeks after the onset.