Porcine cells express more than one functional ligand for the human lymphocyte activating receptor NKG2D.

Background: Xenotransplantation could ameliorate the severe shortage of donor organs. The initial results of transplantation from genetically-modified pig donors to primate recipients suggest that hyperacute rejection can be overcome, but thrombotic microangiopathy and the human anti-pig cellular immune response remain as significant impediments to successful clinical xenotransplantation. NKG2D is an activating immunoreceptor found on human natural killer (HuNK) cells, CD8(+) and gammadelta T cells.

Glycosylation changes in hFUT1 transgenic mice increase TCR signaling and apoptosis resulting in thymocyte maturation arrest.

Glycosylation of cell surface proteins is important in thymocyte maturation. In particular, the level of sialylation of key glycoproteins such as CD45 is believed to play a major role in regulating TCR signaling, adhesion and apoptosis of developing thymocytes. We show here that transgenic expression of human alpha1-2 fucosyltransferase (hFUT1) in mice resulted in a marked shift from sialylation to fucosylation of thymocyte glycoproteins.

The human cytomegalovirus glycoprotein UL16 traffics through the plasma membrane and the nuclear envelope.

The human cytomegalovirus (HCMV) UL16 gene encodes a glycoprotein that interferes with the immune response to the virus-infected cell. In vitro, UL16 interacts with MICB and ULBPs that are ligands for the stimulatory receptor NKG2D, expressed on NK cells and CD8(+)T cells. UL16 expression has been shown to promote intracellular accumulation of MICB, ULBP1 and 2 and thus, interfere with the immune response to HCMV-infected cells.

Persistent expression of CD94/NKG2 receptors by virus-specific CD8 T cells is initiated by TCR-mediated signals.

Subsets of CD8 T cells express receptors that are critical in regulating the activity of NK cells. To characterize the expression of these receptors on CD8 T cells we made use of transgenic mice that express a H-2Kb restricted TCR specific for the immunodominant epitope located within the HSV-1 glycoprotein B (gB). Few naive gB-specific T cells express Ly49 or CD94/NKG2 receptors.