Specific Detection of Neu5Gc in Animal Tissues by Immunohistochemistry

One of the major obstacles in xenotransplantation is tissue expression of the non-human mammalian carbohydrate N-glycolylneuraminic acid (Neu5Gc). This 9-carbon backbone acidic sugar is the hydroxylated form of N-acetylneuraminic acid (Neu5Ac), and both constitute the two most common sialic acid types in mammals. Loss of CMP-Neu5Ac hydroxylase encoding gene in humans dictates the immunogenic nature of Neu5Gc-containing xenografts. Here we describe an immunohistochemistry method for the detection of Neu5Gc in mammalian-derived tissues using affinity-purified chicken anti-Neu5Gc IgY. Specificity is further demonstrated by competitive inhibition with free Neu5Gc or Neu5Gc-glycoproteins, but not with Neu5Ac or Neu5Ac-glycoproteins. This method can be used to evaluate potential Neu5Gc-immunogenicity of xenografts.