CD4+CD25 + Foxp3+ T-reg cells play an important role in na(i)ve immune tolerance in rat liver transplantation

Objective To study the effect of CD4+ CD25+ Foxp3 + T-reg cells in na(i)ve immune tolerance using a rat liver transplantation model, we monitored the changes of this population cell of CD4+ CD25+ Foxp3+ T-reg cells in liver、thymus、spleen and blood by flow cytometry technique. Methods Na(i)ve immune tolerance model of rat liver transplantation was established (LEW→DA) ,The rejection group (DA→LEW) was used as the control group. CD4+ CD25+ Foxp3+ T-reg cells were respectively extracted and measured in liver、thymus、 spleen and blood. Simultaneously, we recorded the survival rate of rats and liver graft pathological changes in every group. The expression level of Foxp3 mRNA in every group was monitored. Results DA rat in tolerance group could acquire long-time survival without any immunosuppressive drug. Compared with rejection group,CD4+ CD25+ Eoxp3+ T-reg cells in tolerance group were significantly increased, especially in blood. The expression level of Foxp3 mRNA is significantly higher(P<0. 05). Conclusions In tolerance group (LEW→DA), the number and percentage of CD4 + CD25 + Foxp3 + T-reg cell were both significantly increased. It suggests that CD4 + CD25 + Foxp3 + T-reg cells play an important role in na(i)ve immune tolerance model of rat liver transplantation. This new sight could lead to induction immune tolerance and suppression graft rejection. Key words: Liver transplantation;  Immune tolerance;  T lymphocytes, regulatory