The Roles of Cd4+Cd25+ and Cd8+Cd103+ Regulatory T Cells in Mice Corneal Rejection

Abstract

Purpose: : To study the changes of CD4⁺CD25⁺ and CD8⁺CD103⁺ regulatory T cells and their correlated cytokine in corneal allograft transplantation in mice.

Methods: : BABL/c (H-2^d) received corneal allografts from C3H/He (H-2^k) were the allograft group, and BABL/c (H-2^d) were the donor as well as the recipient in the isograft group. The corneal graft survival time was recorded. Pre-, 3 days, 7 days, 4 weeks and 8 weeks post-operatively, the infiltration of inflammatory cells and the corneal neovascularization was evaluated by histopathology, the percentage of CD4⁺CD25⁺ and CD8⁺CD103⁺ T cell in peripheral blood and spleen was determined by flow cytometry, meanwhile, the expression of IL-10, IL-4, IFN-γ and IL-1β in serum and aqueous humor was measured by ELISA.

Results: : The graft rejection in the allograft group occurred from 7 days to 4 weeks, mean (14.10±3.91) days (Figure A-D,I). But the grafts of the isograft group remained clear within the 8 weeks duration of observation(Figure E-H,J) and the survival time is much longer than that of the allografts(Χ²=44.080,P=0.000,Figue K). After transplantation, flow cytometry showed the percentage of CD4⁺CD25⁺Treg in peripheral blood in the isograft group raised much higher than that in the allograft group (P<0.05,Figure M). On the other hand, the expression of CD8⁺CD103⁺T cell in peripheral blood in the isograft group was much lower than that in the allograft group (P<0.05,Figure P). The change of CD4⁺CD25⁺ and CD8⁺CD103⁺ T cell in spleen (Figure N,Q) occurred earlier than that in peripheral blood. ELISA showed the expression of IL-10 and IL-4 in serum in the allograft group post-operatively was much lower than that in the isograft group (P<0.05,Table A,B). Otherwise, the level of IFN-γ and IL-1β in serum in the allograft group grew higher than that in the isograft group (P<0.05,Table C,D). Furthermore, the cytokines in aqueous humor behaved similarly with that in serum.

Conclusions: : The up-regulation of CD4⁺CD25⁺Tregs protected the corneal graft from rejection, which might be assoicated with the high expression of IL-10 and IL-4 . And the raise of CD8⁺CD103⁺Tregs took an important part in allograft rejection, which was likely due to the increased level of IFN-γ and IL-1β.

Keywords: immunomodulation/immunoregulation • transplantation • cornea: basic science