CTLA4-FasL Fusion Protein To Prevent Immune Rejection After Corneal Transplantation In Mice

Objective To investigate therapeutic effect and action mechanism of recombined double-function fusion protein CTLA4-FasL for the prevention of corneal immune rejection. Methods C57BL/6 mice were as donors and BALB/c mice as recipients. The total of BALB/c mice were divided into 5 groups, A group control group (n=20), B group 0.1ug/mLCTLA4-FasL protein treated group (n=8), C group 1.0ug/mLCTLA4-FasL protein treated group (n=8), D group 10ug/mLCTLA4-FasL protein treated group(n=16), E group 20ug/mLCTLA4-FasL protein treated group( n=8). Survival time of corneal allografts was observed and routine experimental examinations were performed postoperatively including immunohistochemistry, reverse-transcription polymerase chain reaction (RT-PCR), TdT-mediated dUTP nick end labeling (TUNEL). Results Allografts survival time was mean 16. 3 + 1. 5 days in A group, 15. 2 + 2. 1 days in B group, 14. 6±1.2 days in C group, over 90 days in D group, 12. 9 + 3. 2 days in E group. Survival time of corneal grafts was markedly prolonged in D group compared with other groups, the longest one more than 120 days (P<0.01). There were much more inflammatory cells and lymphocytes spreading in edematous corneal stroma of rejected allografts in A group than that in clear allografts in D groups by histopathological examination. Negative expression for cytokines IL-10 and IL-12 in rejected corneal grafts and positive expression for CD80 were observed in rejected iris by immunofluorescent technique in A group. Above cytokines were undetectable in D group. CD80 and CD86 mRNA increased in iris in A group and disappeared in D group with RT-PCR examination. Abundant apoptosis cells were visible in grafts treated with CTLA4-FasL proteins, but a few apoptosis cells were visible in A group. Conclusions 10 ug/mL fusion protein CTLA4-FasL is able to prolong survival time of corneal grafts and induce immune tolerance.