Adhesive interactions between human NK cells and porcine endothelial cells

Human natural killer (NK) cells are able to adhere to xenogeneic porcine en dothelial cells (EC) and evidence from in vitro studies as well as animal m odels suggests a potential role fur NK cells in the cellular recognition an d damage of porcine xenogeneic tissues. One possible explanation for the ob served NK cell-mediated xenogeneic cytotoxicity against porcine EC is the m olecular incompatibility between porcine major histocompatibility complex ( MHC) class I molecules and MHC-specific inhibitory receptors on human NK ce lls. In this review we attempt to summarize the current knowledge concernin g adhesive interactions between human Mt cells and porcine EC under special considerations of the cross-species receptor-ligand interactions. Methodol ogical differences in assessing adhesion between various studies are review ed and comparisons to the syngeneic/allogeneic adhesion mechanisms are made . Finally, the therapeutic potential of blocking antibodies and transgenic HLA expression in preventing NK-cell adhesion and xenogeneic cytotoxicity i s discussed.