Dimethyl dioctadecyl ammoniumbromide as an adjuvant for delayed type hypersensitivity and cellular immunity against Semliki Forest virus in mice.

Intracutaneous immunization of BALB/c mice with inactivated Semliki Forest virus mixed with the cationic, surface active lipid dimethyl dioctadecyl ammoniumbromide produced a strong enhancement of delayed type hypersensitivity without detectable antibodies in serum. Furthermore these mice were more protected against intraperitoneal challenge than normal immunized mice. This protection might be explained by an enhancement of cellular immunity against Semliki Forest virus. Dimethyl dioctadecyl ammoniumbromide by itself has no effect on footpad swelling, mortality and mean survival time.