Cells of porcine epidermis and corneal epithelium are not recognized by human natural anti-α-galactoside IgG

Human natural antibodies against Galal,3Gal-R are mainly responsible for hyperacute rejection of xenografts transplanted to the human host. In addition to the anti-α-Gal activity, human serum also contains anti-(-Gal IgG fractions. Employing biotinylated IgG subfractions with anti-α- and anti-βGal activity purified from human natural IgG, we have studied expression of reactive epitopes in porcine and human skin, porcine cultured keratinocytes and porcine and human cornea, porcine liver and human lacrimal gland, tear fluid and capillaries. No reactivity of porcine and human epidermis as well as anterior corneal epithelium was observed for human anti-α-Gal IgG. Serving as positive control, porcine capillaries gave the expected signal with the anti-α-Gal antibody. The anti-(-Gal subfraction recognized cell nuclei in the epidermis of both these species. The pig liver cells interacted with antibodies against α and (3-galactosides like cells of the human lacrimal gland. α-galacto-side-reactive glycoproteins were also detected in the human tear fluid. The carbohydrate specificity of the reaction was ascertained by using melibiose as competitive sugar for a-galactoside-mediated binding. These results reveal the presentation of Galal,3Gal in epithelial cells of human lacrimal gland, its biosynthetic origin being unclear. With respect to a potential clinical perspective, the given results facilitate consideration of the use of porcine epidermal cells in engineering of non-permanent wound covers to improve treatment.