Figure 4.

Effect of preimmunization with DMBA on subsequent DMBA–DNA adduct formation in the skin of C3H mice. Mice were immunized with DMBA by painting 100 μg on the abdominal skin. [³H]DMBA was applied to the back skin 5 days later. Skin was removed and [³H]DMBA binding to DNA was assessed 24 hr after that. Positive controls were immunized with DMBA before [³H]DMBA application. Negative controls were not immunized. The data are significant at the P < 0.01 level.