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 molecu les are essential for graft rejection. However, to determine the specific r ole 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 vari ous transfectant cell lines mas determined. Results. C3H.B35 skin and heart grafted 60 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 expre ss 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 al lo-MHC class I-incompatible grafts, and these mice are valuable to elucidat e the role of HLA class I molecules in transplantation.