The effects of four mycotoxins on the mitogen stimulated proliferation of bovine peripheral blood mononuclear cells in vitro.

The effects of four mycotoxins, T-2 toxin, deoxynivalenol (DON), ochratoxin A (OTA) and fumonisin B1 (FB1) on the response of bovine peripheral blood mononuclear cells (PBM) in vitro to the mitogens concanavalin A (Con A), phytohaemagglutinin A (PHA) and pokeweed mitogen (PWM) were assayed after 4 days' incubation using 3H-thymidine uptake and the MTT bioassay. The concentrations of mycotoxin required to reduce the proliferative response of PBM by 50% for Con A, PHA and PWM as measured by 3H-thymidine incorporation was for T-2 toxin 0.30, 0.40 and 0.18 ng ml-1; for DON 0.07, 0.09 and 0.04 microgram ml-1; for OTA 0.10, 0.20 and 0.15 microgram ml-1, and for FB1 35, 18 and 11 micrograms ml-1 respectively. The concentrations of mycotoxin required to reduce the proliferative response of PBM by 50% for Con A, PHA and PWM as measured by the MTT bioassay were for T-2 toxin 2.0, 2.0 and 1.0 mg ml-1; for DON 0.70, 0.50 and 0.50 microgram ml-1; OTA 1.5, 1.5 and 1.5 micrograms ml-1; and FB1 > 50, > 50 and 20 micrograms ml-1 respectively. Further cytotoxicity assays including the LDH bioassay and Trypan blue exclusion were performed only on Con A-stimulated PBM cells after 72 h incubation. With the LDH-bioassay the 50% inhibition levels were T-2 toxin 0.3 ng ml-1, DON 0.4 microgram ml-1, OTA 1.4 micrograms ml-1 and FB1 3.5 micrograms ml-1; for Trypan blue uptake the 50% inhibition levels were T-2 toxin 5 ng ml-1, DON 2.3 micrograms ml-1 and OTA 4 micrograms ml-1 respectively.