FACTORS INVOLVED IN THE INDUCTION OF NON-SPECIFIC RESISTANCE TO STREPTOCOCCAL INFECTION IN MICE BY ENDOTOXIN

Abstract

Endotoxins derived from several species of gram-negative bacteria, while inducing non-specific resistance to typhoid bacilli in mice, failed to increase the resistance of these animals to infection with virulent strains of group A streptococci. However, if administration of endotoxin was followed by injection of minute amounts of type-specific antiserum, a substantial degree of protection against the streptococcal pathogen was obtained. Injection of the same amount of type-specific antiserum alone did not have any effect on the outcome of the streptococcal infection. Fresh rabbit blood from animals pretreated with endotoxin, together with anti-M protein immune serum, became strongly bactericidal for streptococci. These observations suggest that, at least with regard to streptococcal infection, both humoral and cellular factors are required for induction of non-specific resistance.