Immunotoxicity of mycotoxins.

The immune system is primarily responsible for defense against invading organisms. The effects of several mycotoxins on the immune responses have been investigated; however, most data concern laboratory animals. In some instances, farm animals and cells derived from livestock species have been employed to evaluate the immunotoxicity of mycotoxins. Immune responses are highly variable, and cost considerations usually preclude the use of dairy cattle as experimental models. Immunosuppression caused by aflatoxin B1 has been demonstrated in various livestock species (e.g., turkeys, chickens, and pigs) and also in laboratory animals (mice, guinea pigs, and rabbits). The response of bovine lymphocytes to aflatoxin in vitro is similar to that of other laboratory animals. Trichothecenes are potent immunosuppressive agents that directly affect immune cells and also modify immune responses as a consequence of tissue damage elsewhere. Sheep and calves treated with fusarium T-2 toxin develop leukopenia and decreased functioning of peripheral lymphocytes. Immunosuppressive effects of ochratoxin A, rubratoxin B, and patulin have been reported. Citrinin produced lymphopenia but stimulated responses against antigens. Antibodies against mycotoxins conjugated to proteins have been produced and are useful for analytical purposes.