This study aims to investigate the effects of anti-CD25 monoclonal antibody (mAb) on the effector T cells (Teff) and CD4+CD25+ regulatory T cells (CD4+CD25+Treg) in corneal allograft rejection. Wistar rats were used as donors and SD rats were used as recipients. Routine penetrating keratoplasty (PKP) was performed. 90 SD rats were randomly divided into 5 groups: A - E. Group A (n = 6) was normal group and rats in Groups B (n = 24), C (n = 18), D (n = 18) and E (n = 24) were transplanted and subconjunctivally treated with normal saline, 100 μg anti-CD25 mAb, 100 μg anti-CD25 mAb plus 50 μg dexamethasone and 100 μg dexamethasone, respectively, on day 0, 2, 4, 6 and 8 following transplantation. The average transplant survival time in the Group B was significantly shorter than that of Groups C, D and E (P < 0.05). The mRNA expression of IFN-γ, CD25 or FOXP3 was not detected in the Group A. Compared to the Groups C, D and E, the mRNA expression of IFN-γ and CD25 in the grafts of Group B was markedly increased (P < 0.05) on day 11 following PKP. Compared with the Groups D and E, the mRNA expression of FOXP3 in the grafts of Group C was markedly decreased (P < 0.05). When compared with Group B, the mean IFN-γ level in the aqueous humour was remarkably decreased in Groups C, D and E (P < 0.05) on day 6 and 11 following PKP 11 days after PKP, the mean IFN-γ level in the aqueous humour of Groups D and E was profoundly decreased compared to the Group C (P < 0.05). No significant difference was observed in Groups D and E. But high-dose dexamethasone monotherapy have a high risk of side effects. The results suggest Teff and CD4+CD25+Treg play important roles in the corneal allograft rejection.

 

Key words: Anti-CD25 monoclonal antibody, CD4+CD25+ regulatory T cell, effector T cell, corneal transplantation.