Cell-mediated graft rejection observed in two lines of human histocompatibility leukocyte antigen class I transgenic mice.

Background. Human histocompatibility leukocyte antigen (HLA) class I molecules are essential for graft rejection. However, to determine the specific role of these molecules in clinical situations is difficult. We investigated the applicability of HLA class I transgenic mice (C3H.B35 and C3H.B51) for elucidation of the role of HLA class I molecules. Methods. Skin or heart grafts were transplanted. Cytotoxic T cells (CTL) of C3H.B51 against C3H.B35 were generated and their cytotoxicity against various transfectant cell lines was determined. Results. C3H.B35 skin and heart grafted to C3H.B51 were rejected within 17 and 28 days, respectively. Cytotoxic T cells generated from C3H.B51 showed cytotoxicity against a HLA-B * 3501-transfectant cell line that did not express H-2 molecule, which indicates that these cytotoxic T cells recognize HLA-B35 molecules directly without H-2 restriction. Conclusion. Our results suggest that C3H.B51 recognize C3H.B35 grafts as allo-MHC class I-incompatible grafts, and these mice are valuable to elucidate the role of HLA class I molecules in transplantation.