Cell-mediated immune response in mice during the two-step carcinogenesis experiment by 7,12-dimethylbenz(a)anthracene and 12-O-tetradecanoylphorbol-13-acetate.

Cell mediated immune response in ICR mice during the two step carcinogenesis experiment induced by DMBA plus TPA was followed by determining the delayed type hypersensitivity to two antigens, i.e. DNFB applied to skin and SRBC injected intraperitoneally. In mice developing tumors from 3 to 15 weeks after DMBA initiation, delayed type hypersensitivity to DNFB was suppressed to as low as 30% that of normal mice. This suppression was not recovered by treatment of indomethacin. No difference in delayed type hypersensitivity to SRBC was observed on between the mice on the two-step carcinogenesis experiment and normal mice.