[Production of antirickettsial sera by immunizing horses. II. Obtaining and testing an immune serum to D. sibericus].

The authors present the results of immunization of horses-producers with a commercial antigen and the yolk culture of the living R. sibericus (strain K1) for the purpose of obtaining specific immune sera for many purposes. It was shown that the original combined scheme of immunization and reimmunization of horses, successfully approved in the preparation of immune sera to Rickettsia prowazeki also proved to be highly effective for obtaining the antisera to R. sibericus. Sera obtained after the primary immunization of horses could be successfully used as diagnostic sera, but they were of no use for the preparation of fluorescent antibodies and the highly active hemosensitin; as to the sera obtained after the remote reimmunization--they were universal raw material. Dry fluorescent antibodies to R. sibericus were prepared of the horse sera (their stain titre was 1 : 256--1 : 512) a highly active hemosensitin, and also dry commercial diagnostic sera for the IHT, CFR and the immunofluorescent reaction of microagglutination.