The comparative selectivity of adjuvants for humoral and cell-mediated immunity. II. Effect on delayed-type hypersensitivity in the mouse and guinea pig, and cell-mediated immunity to tumour antigens in the mouse of Freund's incomplete and complete adjuvants, alhydrogel, Corynebacterium parvum, Bordetella pertussis, muramyl dipeptide and saponin.

Corynebacterium parvum was the only adjuvant of those tested which consistently potentiated delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) in the mouse, although this required the antigen-adjuvant mixture to be injected subcutaneously in the footpad rather than the flank. For induction of DTH to ovalbumin (OVA) in the guinea pig, C. parvum and MDP could be substituted for the mycobacteria in FCA. C. parvum was effective in aqueous solution provided that the OVA was absorbed onto alhydrogel. Saponin also potentiated DTH when injected with OVA in aqueous solution. C. parvum was the sole adjuvant of those tested to promote protective cell-mediated immunity (CMI) to M4 fibrosarcoma cells. It is concluded that C. parvum is a promising candidate adjuvant for promoting CMI induction without recourse to a water-in-oil emulsion.