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

Abstract

Summary

1. Precipitin tests in semi-solid agar (gel-precipitin) have been carried out between concentrates of streptococcal culture supernates and sera of various sources. Two technics of diffusion in 1 dimension (tube) were used: the single-diffusion technic of Oudin, and a double-diffusion technic. 2. 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. 3. Sera of patients with acute rheumatic fever and of patients convalescent from an acute streptococcal infection (scarlet fever) were also tested by this technic 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 technic. The corresponding ranges found with the single-diffusion technic 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 6 weeks after the onset of the infection than 3 weeks after the onset.