Influence of mild acid hydrolysis on the antigenic properties of phase I Coxiella burnetii.

Mild acid hydrolysis of phase I Coxiella burnetii cells gradually cleaved off polysaccharide chains, which contain determinants of antigen 1, thus unmasking determinants of the diagnostically important antigen 2. This artificial phase I to phase II conversion was reflected by changed serological activity in the complement-fixation (CF) test and by changed nonspecific phagocytosis. The product of mild acid hydrolysis can serve as a complex diagnostic preparation, because it reacts in the CF test with antibodies directed to both C. burnetii antigens.