Effects of a commercial malathion dip preparation on the cellular and humoral immune response of BALB/c mice.

Because of the widespread use of malathion as a treatment for ectoparasitism, a study was undertaken to determine the effects of a malathion dip preparation on the BALB/c mouse immune system. Mice were treated with either 2% (recommended dosage) or 8% solutions of malathion or a water control. The cellular immune response was evaluated by in vitro exposure of lymphocytes to mitogens, and the humoral immune response was assessed by using an enzyme-linked immunosorbent assay (ELISA) to quantify antibody production against sheep red blood cells (SRBC). Responses to the mitogens and to the SRBC were not significantly different between 2% and 8% malathion treated and water treated mice. Results indicated that malathion did not affect these two aspects of the mouse immune system when used as a 2% or 8% dipping solution.