Immunological consequences of dioctyltin dichloride (DOTC)-induced thymic injury

Inbred rats fed diets containing 75 ppm dioctyltin dichloride (DOTC) for 8 or 12 weeks demonstrated marked reduction in thymic weight. This reduction was accompanied by a decrease in the number of W3/25 positive phenotypic circulating lymphocytes and an impaired ability to respond to suboptimal mitogenic stimulation. Responsiveness to alloantigenic stimulation, as measured by mixed leucocyte reactions, was depressed in DOTC-fed animals whereas no effect on natural cytotoxicity in nonimmunized treated or control rats was evident. No difference was found in the ability of treated compared to untreated animals to mount specific antibody responses against sheep red blood cells, and no evidence was found to indicate toxicity to lymphocytes in vivo. The investigation showed that DOTC administration resulted in a selective immunodeficiency.