The soluble antigens of Rickettsia prowazeki, R. typhi and R. canada. Investigation of their interrelationship by various serological methods.

The purpose of this research is the isolation of an eventual species-specific fraction from the "soluble antigen" of Rickettsiae. The "soluble antigen" of R. prowazeki (Breinl strain), R. typhi (Wilmington strain) and R. canada were purified at 25% saturation with ammonium sulphate (PSA). Corresponding antisera were produced in rabbits. The serological methods used were the complement fixation, the micro-agglutination, the precipitation method in capillary tubes and the immuno-diffusion method carried out with complete and previously cross-absorbed antisera. Furthermore, the PSA were subjected to immuno-electrophoretic and disc electrophoretic fractionation. The PSA of R. prowazeki was found to contain at least 4 group-specific fractions. A species-specific component could be demonstrated with certainty only with the precipitation method in capillary tubes carried out with previously cross-absorbed antisera. The PSA of R. typhi contains 5 fractions of which 4 are group-specific and one is species-specific. This result was confirmed by all methods. The PSA of R. canada: the maximum of 3 components could be detected with the help of immuno-electrophoretic fractionation. A fourth antigenic determinant was made apparent by the presence of corresponding antibodies in the anti-R. canada PSA only.