[Study of the immunobiological properties of a soluble antigen of Rickettsia prowazekii in an experiment].

The results obtained in the study of the immunobiological properties of R. prowazekii soluble antigen purified without the use of ether are presented. The effectiveness of this antigen has been shown to be not inferior to that of preparations obtained by ether purification. It is expedient to introduce the antigen in the adsorbed form in two injections at an interval of 10--14 days, as immunization in two injections produces phase changes in the immune responsiveness of animals.