Chapter 36 - Immunotoxicity of Pesticides

Abstract

The influence of pesticides on the immune response in humans has largely been ignored. Although exposure to a dose of compound sufficient to cause acute poisoning may have an effect on the immune system, many studies have examined the effects of pesticides on the immune system, with particular emphasis on the administration of a nontoxic dose of compound. The immune-mediated complications of pesticide exposure to humans that are most often noted are allergic reactions, especially contact dermatitis. In most of studies on the effects of dichlorodiphenyltrichloroethane (DDT) on the immune system DDT has been shown to increase, have no effect on, or decrease the immune system depending upon the dose, route, timing of administration, species, and antigen. Studies show that the immune system was most sensitive to chlordane-induced immunotoxicity when exposure occurred in utero. A study conducted to examine the effects of toxaphene on the immune system showed a decreased humoral immune response to bovine serum albumin and phagocytosis by peritoneal macrophages, but no effect on the delayed-type hypersensitivity (DTH) response to tuberculin antigen. The murine immune system was found to be most sensitive to the immunotoxic effects of chlordane when exposure occurred in utero in a variety of systems. Studies show that a variety of organophosphate pesticides reduce immune function in a variety of species. Carbamates were shown either to not affect or to suppress the generation of immune responses depending upon the dose, route, and timing of exposure.