Variable expression of delayed hypersensitivity in different mouse strains using dimethyl dioctadecyl ammonium bromide as an adjuvant.

Delayed-type hypersensitivity measured as footpad swelling was studied in large number of inbred mouse strains. A conjugate of bovine serum albumin (BSA) with the small 2,4-dinitrophenyl (DNP) hapten served to generate strong reactions, specific for the DNP group. Delayed hypersensitivity was produced with the DNP-BSA complex mixed with the cationic, surface active lipid, dimethyl dioctadecyl ammonium bromide (DDA). Great variation was observed in delayed hypersensitivity among different mouse strains. For convenience, the mice were classified into five groups, notably: non-, low, moderate, good and high responders. The highest responding animals were BALB/cJ mice, the lowest were P/JN and outbred nu/nu mice. No correlation was observed between H-2 type and the intensity of the elicited reactions.