REMOVAL OF ANTIPORCINE NATURAL ANTIBODIES FROM HUMAN AND NONHUMAN PRIMATE PLASMA IN-VITRO AND IN-VIVO BY A GAL-ALPHA-1-3GAL-BETA-1-4-BETA-GLC-X IMMUNOAFFINITY COLUMN

Background, Natural antibodies (NAbs) against a terminal alpha 1-3 gal actosyl (alpha Gal) epitope have been identified as the major human an ti-pig NAbs, Methods and Results. We used two synthetic alpha Gal tris accharides-type 6 (alpha Gal6) and type 2(alpha Gal2)-linked to an ine rt matrix to remove NAbs from human plasma in vitro, Flow cytometry in dicated that an average of 85% of the NAb binding activity was deplete d by adsorption with alpha Gal6. By measuring the binding of NAbs to p ig peripheral blood mononuclear cells and bone marrow cells, we demons trated that alpha Gal6 was more effective than alpha Gal2 in removing NAbs, and the combination of alpha Gal6 + alpha Gal2 did not further i ncrease removal of NAbs, The specificity of the removal of NAbs (IgM a nd IgG) reactive with the alpha Gal epitope by alpha Gal6 matrix was s hown by enzyme-linked immunosorbent assay, In vivo studies in nonhuman primates compared plasma perfusion through a alpha Gal6 immunoaffinit y column with hemoperfusion through a pig liver for changes in blood p ressure, hematocrit, platelets, and NAb adsorption, Conclusions, Both methods reduced the level of anti-pig IgM and IgG xenoreactive antibod ies to nearly background, but column perfusion caused less hypotension and reduction in platelets than liver perfusion, Four pig kidneys tra nsplanted into monkeys after column perfusion did not undergo hyperacu te rejection, remaining functional for 2-10 days, with a mean function al period of 7 days, demonstrating that a pig kidney can support renal function in a primate.