Serological relatedness of mouse-virulent Yersinia enterocolitica.

An antiserum (WA-SAA) was produced which agglutinated specifically with mouse-virulent but not with avirulent strains of Yersinia enterocolitica. Expression of the antigenic determinant(s) reaction with WA-SAA was temperature dependent; for growth temperatures of 20 to 40 degrees C, agglutination titers were lowest for cultures grown at 20 degrees C and highest for cultures grown at 35 to 40 degrees C. Addition of Ca2+ (2.5 to 10 mM) to the growth medium had little effect on the agglutination titer, and gel diffusion studies with monospecific anti-V serum indicated that V antigen was not likely to be the determinant reacting with WA-SAA. Immunohistological studies of Peyer's patches of mice infected with Y. enterocolitica WA revealed that the antigenic determinant(s) reacting with WA-SAA was expressed in vivo. The strong correlation of agglutination titer with mouse virulence and the expression in vivo of the antigenic determinant(s) reacting with WA-SAA suggest that the antigen(s) may be associated with the pathogenicity of Y. enterocolitica.