[Changes of CD4+ CD25+ and CD8+ CD28- T regulatory cells in spontaneous tolerance of inbred rat orthotopic liver transplantation].

OBJECTIVE

To explore the roles of CD4+ CD25+ and CD8+ CD28- T regulatory cells in spontaneous tolerance of inbred rats orthotopic liver Transplantation.

METHODS

The orthotopic liver transplantation models of spontaneous tolerance were established between BN (donor) and LEW (recipient) inbred rats whose survival time was more than 120 days, The expression of CD8+ CD28- T and CD4+ CD25+ T cells in PBMC and spleen were determined by flow cytometry. CD8+ CD28- T and CD4+ CD25+ T cells were sorted by immunomagnetic beads. The expressions of CD25, CD28, CD152 and CD45RO on CD8+ CD28- T and CD4+ CD25+ T regulatory cells were also determined by flow cytometry.

RESULTS

Compared with control groups, the proportion of CD8+ CD28- T regulatory cells in spontaneous models was significantly increased in peripheral blood mononuclear cells (PBMC) and spleen [PBMC (30.2+/-5.8)% vs (16.4+/-6.1)%; Spleen (23.7+/-7.2)% vs(13.4+/-5.5)% P<0.01]. CD4+ CD25+ T regulatory cells had no change; CD11b was expressed on CD8+ CD28- T regulatory cells in both control groups and tolerance groups, and CD25, CD152 (CTL-4) were not expressed on CD8+ CD28- T regulatory cells. The expression of CD45RO on CD8+ CD28- T regulatory cells was 76.1% in control groups and more than 90% in tolerance groups; CD11b, CD152 (CTL-4) and CD45RO were expressed on CD4+ CD25+ T regulatory cells in both control groups and tolerance groups.

CONCLUSION

The roles of CD8+ CD28- T cells were more important than CD4+ CD25+ T cells in spontaneous tolerance of rat liver transplantation. the different expressions of CD152 showed the functions of CD8+ CD28- and CD4+ CD25+ T cells were different. The different expressions of CD45RO suggested CD8+ CD28- T regulatory cells was changed before and after liver transplantation.