A comparison of pyrogenicity and related properties seen in a suspension of Corynebacterium parvum and a gramnegative organism.

When the pyrogenic properties of C. parvum and a gramnegative organism, S. typhimurium, were compared it was found that the onset of the pyrogenic response to C. parvum was delayed relative to that of S. typhimurium and that secondary responses rarely occurred. In further experiments the interaction of C. parvum and S. typhimurium was studied. Although synergism was not demonstrated, the kinetics of the response to mixtures of the two vaccines was anomalous while pre-treatment of rabbits with C. parvum resulted in the elimination of the secondary pyrogenic response to S. typhimurium suspension. The implications of these results are discussed in terms of the known characteristics of endogenous pyrogen, lipopolysaccharide and peptidoglycan.