Different requirements for the regulation of transplantation tolerance induction for allogeneic versus xenogeneic major histocompatibility complex antigens.

One way to solve the problem of human donor organ shortage is the use of animal organs. Therefore, it is important to study the T-cell response against xenogeneic major histocompatibility complex (MHC) antigens. In the present study, we have used HLA-B27 transgenic mice in a xenogeneic transplantation model. The results indicate that both transgenic skin transplantation and intravenous (IV) injection of transgenic spleen cells can reverse specific T-cell low responsiveness against the transgenic HLA-B27 antigen into high responsiveness in vivo and in vitro. In contrast, IV injection of spleen cells across an allogeneic H-2 class I disparity results in transplantation tolerance. Thus, despite T-cell low responsiveness against the transgenic HLA-B27 antigen, IV injection of transgenic HLA-B27 disparate lymphocytes does not tolerize, but rather immunizes for the xeno-MHC antigen.