The effect of thiabendazole in a mixed leukocyte culture.

The effect of thiabendazole (TBZ), an anthelmintic, on a mixed leukocyte culture was assessed. Following i.p. administration of TBZ at a dose of 20 mg/kg to C57BL/6 mice, spleen cells were harvested and reacted in a one-way mixed leukocyte culture with irradiated BALB/c stimulator cells. When TBZ was administered 24 hr before the animals were killed, the proliferative response of spleen cells after 5 days in culture was greater than two times that of responder cells from normal, untreated C57BL/6 mice; the reactivity of spleen cells harvested 48 hr after TBZ administration was not statistically different from controls. Although proliferative response of normal responder cells reached a peak on day 6, TBZ treatment 24 hr before the mice were killed caused spleen cells to reach a proliferate peak on day 3. The magnitude of this peak was three times the normal proliferative peak on day 6. The population of spleen cells affected by TBZ is in the plastic-adherent fraction, and the drug effect can be transferred to normal responder lymphocytes by the addition of peritoneal exudate cells from TBZ-treated mice.