Antigenic characterization of Pasteurella pneumotropica isolated from mice and rats.

Antigenic characterization of P. pneumotropica derived from mice and rats were serologically investigated by use of hyperimmune rabbit sera against mouse strain M 1 and rat strain R 1 and absorbed sera m-1 and r-1 which were prepared by absorbing anti-M 1 serum with strain R 1 and anti-R 1 serum with strain M 1, respectively. All of 13 mouse strains employed were agglutinated with both anti-M 1 and anti-R 1 sera, but their agglutination titers with anti-M 1 serum were usually higher than those with anti-R 1 serum. Agglutination test of 13 rat strains with two antisera showed results converse to those of mouse strains. On the other hand, all the mouse strains were agglutinated with absorbed serum m-1 but not with absorbed serum r-1, while quite converse results were obtained with all the rat strains. Antigens reactive with the absorbed sera were remarkably destroyed by heating at 100 degrees C for 1 hour and treating with 1 N HCl, suggesting to be capsular antigens of bacterial cells.