Characterization of cell-mediated immune responses elicited by orthotopic corneal allografts in mice.

Abstract

These results can be explained in the context of "direct" and "indirect" pathways of allorecognition. Because normal corneas lack passenger leukocytes, the potential for direct recognition of alloantigens on orthotopic corneal grafts is small. Therefore, T cells activated by orthotopic corneal allografts must recognize donor-derived antigens primarily on recipient antigen presenting cells, that is, through the indirect pathway of allorecognition. Because minor H antigens are the dominant cellular proteins in grafts, it is proposed that minor H determinants are the most immunogenic alloantigens in orthotopic corneal grafts because they are the major source of peptides that will be loaded onto recipient class II molecules for T-cell recognition. We further predict that long-term acceptance of corneal allografts is promoted when recipient mice acquire anterior chamber associated immune deviation (impaired and suppressed DH) directed at minor H alloantigens of the grafts.