[Serodiagnosis of human Yersinia infections. Preliminary results].

Preliminary data are reported on experience with newly developed complement-fixing (CF) antigens prepared from cultures of type 3 and type 9 Yersinia enterocolitica and from Yersinia pseudotuberculosis. Antigens were immunologically potent and not anti-complementary, thus making it possible to obtain satisfactory serologic tests. The results may be summarized as follows: 1. Yersinia CF antigens do not react with sera from healthy blood donors. There was only one low titer reaction with type 9 antigen among more than 300 serum samples tested. 2. There was a high degree of correlation between results of the agglutination tests and those obtained by CF. 3. There is no cross-reactivity by CF among the three Yersinia antigens if human sera are tested. A complete crossing was, however, obtained between type 9 Yersinia and Brucella abortus. 4. Hyperimmune sera frequently showed marked cross-reactivities in both CF and agglutination tests. 5. Human sera positive for various Salmonellae do not react in the CF tests with Yersinia antigens. It is felt that the new CF antigens may become an important tool for the detection of antibodies against Yersinia enterocolitica in the diagnosis of infectious diseases.