The role of class I and class II MHC antigens in the rejection of vascularized heart allografts in mice.

We have examined the role of entire major histocompatibility complex (MHC) disparity, individual class II or class I alloantigens in the rejection of vascularized heart allografts. Our results demonstrate that entire MHC, as well as both class II and class I disparities, may induce acute heart graft rejection or severe and irreversible heart muscle destruction. However, in 1 of 2 combinations differing at class II and 1 of 5 differing at class I, hearts have shown a good function greater than 100 days postgrafting. Furthermore, each donor-recipient combination has demonstrated a unique pattern of heart allograft function as well as a degree of heart muscle damage. In conclusion, these data suggest that the rejection process depends upon multiple factors such as the immune-response-gene-regulated immunoresponsiveness of the recipient as well as the expression of alloantigens on heart grafts during the induction and effector phases of the immune response.