IMMUNOHISTOCHEMICAL QUANTITATION OF POLYCYCLIC AROMATIC HYDROCARBON-DNA ADDUCTS IN HUMAN-LYMPHOCYTES

The formation of polycyclic aromatic hydrocarbon-DNA adducts was studi ed in peripheral blood lymphocytes obtained from men with occupational and environmental exposure. Subjects included coke factory workers, r esidents from the vicinity of the cokery, and rural region inhabitants (16 individuals in each exposure group). Adducts were determined by i mmunohistochemical analysis using a polyclonal antiserum recognizing b enzo(a)pyrene and related polycyclic aromatic hydrocarbon diol epoxide -DNA adducts, a biotinylated secondary antiserum, and streptavidin-con jugated FITC. Propidium iodide was used to quantitate nuclear DNA. Dua l fluorescence intensities were simultaneously measured with a Zeiss A xiovert microscope and a Bio-Rad MRC-600 argon laser scanning confocal attachment. Adducts were significantly elevated (P < 0.001) in both o ccupational and environmental groups, as compared to the rural control group by Mann-Whitney U test. The distribution of the data indicated the existence of cells with relatively higher adduct levels. The perce ntages of these so called ''higher adduct-level cells'' were 13.6, 11, 5, and 3.7 in cokery workers, environmentally exposed individuals, and rural controls, respectively. The immunohistochemical method allows v isualization and relative quantitation of polycyclic aromatic hydrocar bon-DNA adducts in individual lymphocytes. It requires a much smaller amount of blood than the previously used P-32-postlabeling and ELISA m ethods, which used isolated bulk DNA. It can also be used for adduct q uantitation in biopsy material. The results of this pilot study indica te that this technique is a promising addition to biomonitoring studie s.