ADJUVANTICITY OF LACTOBACILLI .1. DIFFERENTIAL EFFECTS OF VIABLE AND KILLED BACTERIA

Abstract

The adjuvanticity of Lactobacillus brevis and L. plantarum was the subject of this study. The latter was the better adjuvant in [mouse] delayed hypersensitivity and antibody formation to sheep red blood cells. Viable L. plantarum stimulated exclusively the delayed hypersensitivity, where heat-killed bacteria had an adjuvant effect on antibody formation. For optimal adjuvant effects lactobacilli had to be injected in a dose of 108 into the same site as the antigen. Viable lactobacilli and to a lesser degree heat-killed bacteria induce hepato-splenomegaly, suggesting mediation of the adjuvant activity by the RES. Granuloma formation with mainly mononuclear cell infiltrates could be observed after s.c. administration of viable lactobacilli whereas heat-killed lactobacilli induced granulomata containing about equal numbers of granulocytes and mononuclear cells. The possible clinical application of L. plantarum in the immunotherapy of tumors is suggested.