Suppression of human macrophage-mediated cytotoxicity by transgenic swine endothelial cell expression of HLA-G.

Background: Xenotransplantation is an appealing alternative to human allotransplantation because of a worldwide shortage of organs. One of the obstacles for xenografts is cellular rejection by the innate immune system, comprised of NK cells, monocytes, and macrophages. In this study the inhibitory function of HLA-G1, a MHC Ib molecule, on macrophage-mediated cytotoxicity was examined.