Experimental Study. T-cell Vaccine To Induce Transplantation Tolerance

Objective To investigate the effect and the mechanism of T cell vaccination in inducing allogeneic antigen-specific immune tolerance. Methods T cell vaccination(IcTCV, 1TCV) were made from the spleen cells of BN rats , which were induced by Con A and were challenged with the allogeneic specific antigen (spleen cells of LOU/C rat and spleen cells of Lewis rat respectively) . Normal BN rats were vaccinated intraperitoneally with LCTCV, LTCV and RPMI1640 culture buffer (blank control) respectively . One-way mixed lymphocyte reaction(MLR), flow cytometric analysis of the apoptosis of peripheral T cell and the rate of CD4/CD8 in peripheral blood were performed before and after vaccination . Results MLR showed that the immune response capability of BN rat spleen cells in LCTCV group were suppressed significantly after vaccination (P<0.01). In JCV group, the cpm value decreased markedly after vaccination compared withpre-vaccination(P<0.05) . there was not significantly difference between pre- and post-vaccination in blank control group . Comparison of the cpm value at the same timepoints after vaccination between the three groups demonstrated that LCTCV group was lower than JCV group significantly(P<0.01), JCV group was apparently decreased in comparison with the blank control group (P<0.01); In LCTCV group and JCV group, The percentage of peripheral T cell apoptosis was increased significantly after vaccination(P<0.01), The rate of CD4/CD8 of peripheral blood was significantly decreased after vaccination (P<0..01), there was not apparent difference between the LJCV group and LTCV group at the same timepoints after vaccination, there was not significantly difference between pre- and post-vaccination in blank control group.Conclusion Allogeneic Antigen- specific immune tolerance can be successfully induced by T cell vaccination in three weeks;the depletion of specific CD4+ T cell clone may play an critical role in the forming of specific immune tolerance induced by T cell vaccination; the increase of peripheral T cell apoptosis and the decrease of CD4/CD8 can indicate the forming of immune tolerance.