[Factors modulating production of antibodies against Clostridium perfringens in mammals].

Immunogenic properties of Clostridium perfringens type A toxoid preparations obtained by different methods are described. As regards immunogenicity for guinea-pigs and man, toxoid obtained by the detoxification of preliminarily purified alpha-toxin (experimental toxoid) compares favourably with preparations obtained by the detoxification of alpha-toxin in a culture fluid. It was shown in experiments on guinea pigs that immunogenicity of experimental toxoid rises with the increase in the degree of purification of alpha-toxin used for detoxification. The least purified preparations turned out to be the most immunogenic for mice. In Cl. perfringens culture fluid, factor (factors) was found and separated, which reduced the immunogenicity of the respective toxoid in experiments with immunization of guinea pigs and increased it in mice. Activation of antibody-formation was disclosed to be nonspecific. The existence of this factor(s) should be taken into account in the development of vaccines and methods for evaluating their immunogenic properties.