Serologic studies of Brucella suis and Brucella canis

Brucella suis strain 3b and Brucella canis strain RM-6-66 were grown on tryptose agar, and aqueous ether extracts were prepared from the cells. The aqueous phase was clarified by centrifugation for a total of 10 hours at 144,700 times g and fractionated with gels and with diethylaminoethyl (DEAE) cellulose. Two fractions from B suis and 1 fraction from B canis were reactive in the indirect hemagglutination test. The sensitizing ability was destroyed by pronase, but was unaffected by ribonuclease or deoxyribonuclease. Apparently, protein or one of its subunits has an important role in antigenic specificity relating to indirect hemagglutination activity. Results in immunoelectrophoretic analysis indicated at least 22 antigens were in the ultracentrifugal supernate (144,700 times g) of B suis and 31 antigens were in a similar supernate of B canis. Results in immunodiffusion and agglutination absorption studies indicated a close relationship existed between B suis and B canis.