Abstract
Abstract: :
Purpose: To study the characteristics of immune rejection after penetrating keratoplasty (PKP) in CD4 and CD8 knockout mice, and further investigate the mechanism of graft rejection. Methods: Twenty CD4 knockout mice, 20 CD8 knockout mice, and 20 C57BL/6 mice as control group were recipients of corneal allografts from BALB/C donor mice. Grafts were examined by slit lamp, and the time of immune rejection was recorded after PKP. The eyes were collected for immunohistopathologic evaluation, and CD4 and CD8 cells of the anterior segments were examinated at 1, 2 and 4 weeks. All the mice received skin transplantation from BALB/C donor mice at 2 weeks after corneal transplantation. The relation of corneal allograft and skin allograft was evaluated. Results: The corneal graft survival time was more than 90 days in CD4 knockout mice, 28±3 days in CD8 knockout mice and 14±2 days in C57BL/6 mice. There was statistically significant difference (p<0.001) among the three groups. Immunohistopathologic examination manifested little CD8+T cells and no CD4+T cells at corneoscleral limbus and ciliary body in CD4 knockout mice at 2 and 4 weeks after corneal transplantation. In CD8 knockout mice, there were CD4+T cell infiltrates at corneoscleral limbus, iris and ciliary body at 2 weeks after corneal transplantation; at 4 weeks there were much more CD4+T cell infiltrates at corneal beds, iris and ciliary body with some transferred to corneal grafts, and CD8+T cells were not present. The mean survival time of skin grafts was 14±2 days in CD4 knockout mice, 12±1 days in CD8 knockout mice and 10±1 days in C57BL/6 control group. There was statistically significant difference (p<0.001) among the three groups. Conclusions:The gene knockout mouse is a good animal model for the study of immune rejection after corneal transplantation. T cells (mainly CD4+T cells) mediate immune rejection after PKP in mice. Mechanisms of corneal transplantation and skin transplantation may be different.
Keywords: gene/expression • immunomodulation/immunoregulation • transplantation