Antigraft responses to the H-28c antigen by B6 and B6D2F1 mice.

The survival of minor H antigen-bearing skin grafts from donors congenic with C57BL/6 (B6) was compared in B6, B6D2, and AB6 hybrid recipients. In a case singled out for further study, B6 mice were found to reject HW110 skin (H-28c antigen) rapidly, whereas B6D2 mice rejected HW110 skin much more slowly and variably. Both major histocompatibility complex (MHC)-linked and non-MHC genes appeared to affect the survival of HW110 strain skin grafts on B6 and B6D2 recipients. Results of several experiments appear to rule out the sharing of H-28c epitopes between donors and recipients as an explanation for the relatively poor response of B6D2 mice to HW110 skin grafts. Experiments involving bone marrow chimeras produced by the reciprocal exchange of bone marrow between irradiated B6 and B6D2 mice suggest that bone marrow-derived donor cells and non-bone-marrow-derived host cells each contribute to the immune response phenotype with respect to the H-28c antigen. An attempt was made to determine whether B6D2 mice that failed to reject HW110 strain skin grafts possessed suppressor cells specific for the H-28c antigen. Spleen cells from poorly responsive B6D2 mice failed to suppress the rejection of HW110 skin grafts when assayed in immunodeficient mice that were provided with cells from immune B6D2 donors that were highly responsive to HW110 skin grafts.