The prolongation of xenograft survival with human natural xenoantibody elimination

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Hyperacute rejection in xenotransplantation of pig to human is initiated by the interaction of human natural xenoantibodies (XNA) with Gal alpha 1,3 Gal (alpha Gal) epitopes on pig vascular endothelium. One of the strategies for preventing hyperacute rejection is to neutlize XNA by intravenous infusion of alpha Gal containing oligosaccharides. We have synthesized the alpha Gal containing oligosaccharides from galactose by chemical methods, but the chemical synthesis took a great deal of time and required high cost. So we made the disaccharide rho-nitrophenyl-3-0-alpha galactopyranosyl-alpha galactopyranoside (pNP-alpha Gal) using hydrolytic enzyme i.e.alpha-D-Galactosidase from coffee beans at low cost. The ability of this synthetic substance at inhibiting XNA was wxamined by mouse laminin ELISA.pNP-alpha Gal inhibited binding of XNA to laminin as well as chemical synthesized alpha Gal.In addition, we made porcine thyroglobulin (PTg) column which absorbed the XNA,and tried to make the more effective and more specificitic column to eliminate the XNA using the synthesized oligosaccharides. Using magnetic beads coated with PTg, we distinguished B lymphocytes having surface immunoglobulin for alpha Gal from the other B cell. We will estimate the proportion of B lymphocytes capable of synthesizing XNA and examine the distribution of them in human lymphocytes from the spleen, peripheral blood, mesenteric lymph nodes, tonsil gland. Moreover, by activating these B cells with self PHA sup and several mitogen, we are going to establish the system in which (XNA) is exclusively produced.