[Increasing the sensitivity of an immunohistochemical method for detecting carcinogen adducts with DNA]

Application of polyclonal antibodies against N7-methylguanine (N7-MG) for immunohistochemical detection of the DNA damage following exposure to methylnitrosourea in cultured cells (CHO and IAR-27) has been shown. The approaches were applied: a) an extraction of nuclei, and b) a silver intensification of the end product of peroxidase reaction. Both the approaches were effective in increasing the sensitivity of immunohistochemical detection of N7-MG, the latter technique being most sensitive. It is proposed that the silver intensification technique is very perspective to have a high levels of sensitivity and specificity, a sufficient contrast and preservation of the cell morphology. The efficiency of the new approach in application to the purposes of molecular epidemiology is discussed.