Unrelatedness between agglutinations of bacteria and the presence of anti-polysaccharides in sera of Salmonellae from groups B and D.

Rabbits hyperimmunized with two strains of S. paratyphi B provided sera with high agglutinating titers, although the sera were deprived of antipolysaccharide antibodies. However, the polysaccharides of both strains of S. paratyphi B precipitated against anti S. typhimurium sera in which antipolysaccharide antibodies were induced. Antisera obtained with three S. enteritidis strains showed a comparable unrelatedness between the agglutinating titers and the presence of antipolysaccharide antibodies in the corresponding sera. One of the strains, repeatedly used for immunization, never induced antipolysaccharide antibodies, while the agglutinating titers of the sera were high; the polysaccharide of this strain precipitated strongly against anti-Salmonella typhi O 901 sera and against the antisera of the other S. enteritidis strains in which antipolysaccharide antibodies were induced. According to these results, there is no apparent relationship between agglutinations of bacteria and the presence of antipolysaccharide antibodies in the corresponding sera. Heated proteins, isolated from all the strains after previous exhaustive extraction at 37 degrees C, showed strong serological precipitations.