Immunogen sequence: YGVLHPTGPR AKILASSCCA ELLWGIPLPP DVEPMAPEIP GYRGTQVTPT RAVTEQQEDL TADTCLPVFQ VRPMGPPTPL GRPYLPEGPL IKIDMPR Highest antigen sequence identity to the following orthologs: Mouse - 92%, Rat - 92%. XK is a 444 amino acid protein that spans