ABSTRACT
Objective To investigate the expression of CXCR6 in allograft rejection and effect of CXCL16/CXCR6 interaction on allograft survival Methods Intra-abdominal heterotopic heart transplantation was performed using wild type (WT) Balb/c mice (H-2d) (allogeneic) as donors or WT C57BL/6 mice (B6, H-2b) (syngeneic) as donors, and using WT B6 mice as recipients. The intragraft expression of CXCR6 and expression of CXCR6 in CD8+ T cells of the spleens from syngeneic and allogeneic recipients were examined. The allogeneic recipients were further divided into the experimental group (n = 5) and control group (n = 6) randomly. The experiment group and control group were injected with anti-CXCL16 mAb or control mAb respectively until rejection occurred. The cardiac allograft survival in experimental group and control group was evaluated. Results Rejected allografts showed higher expression of CXCR6 than syngeneic cardiac grafts. More importantly,expression of CXCR6 in CD8+ T cells was also up-regulated by allograft rejection. However, injection of anti-CXCL16 mAb could not inhibit cytotoxic activity of CD8+ T cells. Moreover, experimental group could not prolong the cardiac graft survival time as compared with control group. Conclusion Expression of CXCR6 in CD8+ T cells is up-regulated in allograft rejection.
ABSTRACT
Objective To examine the contribution of CD4+ CD25+ regulatory T cells to liver transplant tolerance. Methods After injection of anti-CD25 monoclonal antibody (mAb, PC61), mouse orthotopic liver transplantation was performed and survivals were determined. The paraffin-embedded sections of hepatic allografts were cut and stained with hematoxylin and eosin (HE). Furthermore, the effect of CD4+ CD25+ regulatory T cells on proliferative response of CD4+ T cells and cytotoxicity of CD8+ T cells was examined by depleting these regulatory T cells. Results Depletion of these cells in the recipients but not in the donors before liver transplantation caused rejection. Histological analyses of hepatic allografts with PC61 treatment showed extensive leukocyte infiltration and tissue destruction, whereas those in the control group showed minimal changes. Moreover, elimination of CD4+CD25+ T cells resulted in the enhancement of both proliferative response of CD4+ T cells and cytotoxicity of CD8+ T cells against donor-type alloantigen. Conclusions These results suggest that CD4+CD25+ regulatory T cells were important for tolerance induction to hepatic allografts.