Immunosuppressive Effect of Ochratoxin A in Wistar Rats

Ochratoxins are potent mycotoxins elaborated by Aspergillus and Penicillium species. Incidence of ochratoxin A (OT-A) in feed and natural occurrence of ochratoxicosis in animals have been reported from various parts of the world, including India. In this study, we report the immunosuppressive effect of ochratoxin A in rats. The cell mediated immune responses, as assessed by 2, 4-di-nitro-chloro-benzene (DNCB) induced contact hypersensitivity reaction and macrophage function test ( NO2- production assay) were found to be decreased significantly in OT-A intoxicated rats as compared with those in controls. Humoral immune response, assessed by antibody titres against sheep red blood cells, was also found to be decreased in toxin fed rats. The haemato-biochemical alterations such as leucopenia, lymphopenia and hypoproteinemia associated with OT-A toxicity were also indicative of immunosuppression. These findings suggest that OT-A induces the suppression of both humoral and cell mediated immune responses and must be taken into account while dealing with cases of vaccination failure or frequent bacterial and viral infections in livestock and poultry.