Objective: To investigate the therapeutic effect of double-functioned CTLA4-FasL protein for the prevention of immune rejection in murine corneal allografts.
Methods: It was a experimental study. C57BL/6 mice (n = 45) were as donors and BALB/c mice (n = 90) as recipients. BALB/c mice accepted penetrating keratoplasty were randomly divided into 3 groups including no therapy (A), CsA DDS implanted in anterior chamber (B), 10 microg/mL CTLA4-FasL (C). Survival time of corneal allografts was observed and routine assays were performed including immunohistochemistry, reverse-transcription polymerase chain reaction (RT-PCR), TdT-mediated dUTP nick end labeling (TUNEL).
Results: Survival time of corneal transplants was (14.3 +/- 1.3) days, (58.0 +/- 2.8) days, (106.3 +/- 17.5) days respectively. There was significant difference between groups in statistics analysis (P = 0.000). Inflammatory cells, predominant for CD4 + T cells, showed an increasing tendency for rejected corneal allografts in A group, peaked on postoperative 7 d and then decreased in C group compared with invisible in B group. CD80 or CD86 was detected on postoperative 3 d or 7 d respectively in excised cornea and iris of both A and B group, while either showed weakening expression in C group. On postoperative 14 d, IL-10, TNF-alpha, IFN-gamma mRNA were only detected in rejected cornea allograft of A group other than clear allografts of B or C group. Compared with no apoptosis in the other groups, abundant apoptosis cells were visible in cornea and iris of C group on postoperative 7 d.
Conclusions: CTLA4-FasL is able to prolong survival time of corneal allografts by dual action mechanism to exert immunosuppressive effects, both blockade of CD28-CD80/86 pathway and induction of apoptosis of T cell.