THE INHIBITORY EFFECT OF T-2 TOXIN ON TOLERANCE INDUCTION OF DELAYED-TYPE HYPERSENSITIVITY IN MICE

Abstract
Mice injected i.v. with 1 .times. 109 sheep red blood cells (SRBC) showed no delayed-type hypersensitivity (DTH) response to SRBC and were unresponsive to DTH induction by s.c. injection of an optimal dose of SRBC. When treated with T-2 toxin, a mycotoxin [from Fusarium sp.], 2 days after the i.v. injection, mice showed significant DTH response and were responsive to the DTH induction by the s.c. injection. When the spleen cells of the mice receiving the i.v. injection were transferred to unsensitized syngeneic recipients, the DTH response of the recipients to SRBC was suppressed. The suppressor activity of the spleen cells was decreased by T-2 toxin treatment. By the i.v. injection, cell population of the spleen was increased and that of the thymus decreased. By T-2 toxin treatment 2 days after the i.v. injection, cell population of the spleen was not increased and that of the thymus was markedly decreased. The ratio of .theta.-bearing cells was increased in the spleen by the i.v. injection. Such increase was not observed after the T-2 toxin treatment. The ratio of Ig[immunoglobulin]-bearing cells in the spleen was not changed by the i.v. injection and the T-2 toxin treatment after the i.v. injection. T-2 toxin apparently interferes with generation of suppressor cells for the DTH response.