Promutagenic methylation damage in liver DNA of mice infected with Schistosoma mansoni.

Male and female BK-TO mice were infected with different numbers of Schistosoma mansoni cercariae under standard environmental conditions. Promutagenic methylation damage (O6-methyldeoxyguanosine; O6-MedG) was detected in liver DNA, but not in kidney, spleen or bladder DNA of infected animals. It was shown that levels of hepatic O6-MedG increased with increasing intensities of schistosomal infection. Possible mechanisms of action are discussed. These include the activating effects of schistosomes and their products on murine macrophages and subsequent endogenous formation of N-nitroso compounds by the activated macrophages.