[Tolerance to a xenotransplant in an adoptive system].

Splenocytes of mice tolerant to rat neonatal heart graft were unable to respond to rat blood cells (RBC) when transferred adoptively to lethally irradiated syngeneic recipients 10 or 30 days after tolerogenic treatment. Early after induction of tolerance spleen cells of experimental mice were also unable to respond to sheep red blood cells. However, they responded vigorously to goose red blood cells. Later on (30 days after treatment) tolerance was found to be strictly RBC-specific. Cells suppressing anti-RBC response of intact cells were detected in the spleen of mice both 10 and 30 days after the induction of tolerance. Their suppressive activity was strictly RBC-specific. The results obtained show that early after tolerogenic treatment experimental mice are unable to respond due both to the deficiency of T-helpers involved in the response to mammalian blood cells and to activation of RBC-specific I-J+ T-suppressors. Thirty days after treatment tolerance is maintained solely by RBC-specific T-suppressor cells.