[Antigenic structure of strains of Pasteurella multocida].

Studied was strain Pasteurella multocida-547 isolated from pigs affected with an acute Pasteurella infection. Serologically and immunologically its antigen was most closely related to the antigen of strain R-473. The main somatic antigen was 0:6, and the antigenic formula was 6:B. Homologous sera were used to demonstrate the presence of subsidiary antigens by which the newly isolated strain differed from strains R-473 (6:B), 1235 (6:E), and 989 (11:B). The immunodiffusion test with proper sera and heat-resistant water-soluble antigens could yield results that correlate with the typing of P. multocida strains by capsule and somatic antigens as established through other methods.