Purification, immunotoxic effects, and cellular uptake of trichothecene mycotoxins

Studies were carried out to better understand how the trichothecenes alter immune function in animals and humans. Deoxynivalenol (DON) was purified for use in animal feeding studies. Dietary exposure to DON for 8 weeks altered the serum immunoglobulin profile in mice and decreased the splenic plaque-forming cell response to the antigen sheep red blood cells. The uptake of [3H]T-2 toxin by a murine B-cell hybridoma was studied in order to learn more about the way in which trichothecenes interact with immune cells. A simple procedure was developed for the laboratory production and purification of gram quantities of crystalline DON. When Fusarium graminearum R6576 was grown on rice, concentrations of 600 to 700 ppm DON accumulated after 13 to 18 days of incubation. A DON derivative, 15-acetylDON, was also found at concentrations of 100 to 300 ppm after 7 to 10 days. DON was purified from crude culture extracts by water-saturated silica gel chromatography. Alpha-[3H]T-2 toxin of 99% chemical and radiochemical purity was prepared for use in uptake studies. Both the rate of uptake of [3H]T-2 toxin by hybridomas and the time required for accumulation of [3H]T-2 to reach equilibrium were proportional to the concentration of [3H]T-2. [3H]T-2 toxin accumulated by hybridomas was proportional to the concentration of [3H]T-2 between 10-8 and 10-3 M. The rate of uptake of [3H]jT-2 toxin by hybridomas was inhibited by the trichothecenes T-2 toxin, DON, verrucarin A, and roridin A, as well as the antibiotic anisomycin. The kinetics and concentration dependence of accumulation, along with the inhibition patterns, suggest that uptake of [3H]T-2 toxin by hybridomas is mediated by binding of toxin to ribosomes