The impact of the α1,3-galactosyltransferase gene knockout pig on xenotransplantation

Purpose of review The generation of knockout pigs was a major achievement for the field of xenotransplantation. This review will look at key findings reported within the past 12 months relevant to the role of carbohydrates in the α1,3-galactosyltransferase knockout pig lines. Recent findings The first reports of pig-to-primate solid organ transplantation show that the major barrier to clinical xenotransplantation, hyperacute rejection, has been overcome. These experiments clearly identify the next problem to be addressed by the field, the phenomenon of acute vascular rejection. The role that carbohydrates may still play in the xenograft response is highlighted by the discovery of a second glycosyltransferase that synthesizes Galα(1,3)Gal and the findings that cell surface receptors of natural killer cells recognize Galα(1,3)Gal and N-acetyllactosamine, the carbohydrate epitope exposed in GT knockout animals. Summary With reference to the recent literature, we discuss the issues that we believe need to be addressed before the field may progress towards the clinical reality of using pigs for xenotransplantation.