Immunotoxicologic effects of polychlorinated biphenyls on the cell-mediated and humoral immune systems

Polychlorinated biphenyls (PCBs) have become one of the most widespread and persistent environmental pollutants in the world’s terrestrial and aquatic ecosystems (Risebrough et al. 1968, Johnson and Manske 1976, Kalmaz and Kalmaz 1979). The desirable properties of these aromatic hydrocarbons (relative inertness to chemical and biological degradation, high flash points, and lipid solubility) fostered their use in a wide range of products and electrical systems (Bailey et al. 1970, Rhee and Plapp 1973). These same properties underlie PCB persistence in the environment, uptake by plants (Buckley 1982), and bioaccumulation and biomagnification in animal species (Kimbrough 1974, Kalmaz and Kalmaz 1979). The assessment of the hazard posed by PCBs to human beings and other animals has been confounded by the complexity of the commercial PCB mixtures. These problems arise both from the large number of possible isomers (Dustman et al. 1971) and the presence of contaminants such as chlorinated dibenzofurans (Bowes et al. 1975), chlorinated naphthalenes (Hutzinger et al. 1974), and chlorinated dibenzodioxins (Porter and Burke 1971). Kimbrough (1974) has published an excellent review of the toxicity and physical properties of PCBs to which the reader is reffered for further information.