Hexachlorobenzene-induced effects on the lymphocyte blastogenic response to concanavalin a in the mink and European ferret

Hexachlorobenzene (HCB) was found to depress the lymphocyte blastogenic response of mink (Mustela vison) and European ferrets (Mustek putorius furo) to the plant lectin Concanavalin A (Con-A). A significant reduction in the incorporation of [3H]thymidine was seen in the lymphocytes from adult animals consuming 25 ppm dietary HCB for 8 months. This effect was observed in animals showing no physical signs of distress or toxicity. The in utero and early postnatal exposure of young mink to HCB also resulted in a significant depression of lymphocyte responsiveness. Exposure levels as low as 1 ppm in the dam's diet caused an impaired T-cell response. In the young ferrets exposed to HCB in utero and during nursing, no change in the stimulation index was seen. The monitoring of immunocompetence in animals exposed to toxicants, either through the diet or indirectly via their dam, provides a sensitive indicator of toxicity. Effects were seen in activation of lymphocytes from the mink and ferrets used in this study without grossly observable clinical signs being present.