[Properties of phase I purified cellular antigen of Coxiella burnetii].

An attempt was made to purify phase I cell suspension of Coxiella burnetii used as an antigen in diagnostic serological tests. Homogenised suspension of chick embryos infected with phase I Henzerling and "Z" strains, after preliminary purification from host cell contaminants of chick embryos was subjected to consecutive centrifugation in sucrose/uropoline gradient and to continuous 20-45% uropoline gradient. The fractions obtained from uropoline gradient centrifugation were applied as phase I antigen C. burnetii in the following tests: complement fixation and microagglutination. Only fractions containing protein were serologically active. They proved to be of similar specificity and sensitivity as the antigens obtained by standard method. Moreover, it was found that after formalin treatment of C. burnetii cells no soluble antigens are liberated which could be detected by complement fixation test.