Human Natural Killer Cells and Natural Antibodies Recognize Overlapping Molecular Structures on Discordant Xenogeneic Endothelium

Significant progress towards an understanding of the mechanisms of recognition and rejection of xenogeneic grafts has been witnessed in the past few years. Not only has the molecular basis of discordant xenogeneic tissue recognition begun to become unveiled, but transgenic large animals have been generated that express gene products capable of efficiently interfering with some of the phenomena of immune recognition responsible for graft rejection [1, 2]. Pigs expressing human complement-regulating proteins have been successfully generated, and preclinical transplantation models in primate recipients appear promising [2, 3]. It is easy to foresee that the first clinical trials of discordant xenotransplantation will take place in the near future.