Carbohydrates in xenotransplantation

Area of Science:

• Transplantation immunology
• Xenobiology
• Genetic engineering

Background:

• Allotransplantation faces a critical shortage of human organs.
• Xenotransplantation, using organs from species like pigs, offers a potential solution.
• Significant immunological and physiological barriers exist between pigs and humans due to 80 million years of divergent evolution.

Purpose of the Study:

• To address immunological barriers in pig-to-human xenotransplantation.
• To investigate the role of carbohydrate antigens in xenograft rejection.
• To explore strategies for overcoming immune responses against pig organs.

Main Methods:

• Analysis of carbohydrate epitopes on pig and human cells.
• Genetic modification of pigs to eliminate specific antigens.
• Utilizing nuclear transfer and embryo transfer techniques.
• Investigating the impact of N-glycolylneuraminic acid (Hanganutziu-Deicher antigen) in xenotransplantation.

Main Results:

• Galactose-alpha-1,3-galactose (Gal) on pig vascular endothelium triggers human anti-Gal antibody rejection.
• Pigs lacking Gal expression have been successfully bred by gene knockout of alpha1,3-galactosyltransferase.
• N-glycolylneuraminic acid is another potential target antigen, though its significance is debated.
• Other unidentified antigenic targets on pig cells may also elicit rejection.

Conclusions:

• Eliminating the Gal antigen in pigs is a key step in preventing hyperacute rejection in xenotransplantation.
• Further research is needed to fully understand and address other carbohydrate antigens and unidentified targets.
• Genetic engineering of donor animals is crucial for the future success of xenotransplantation.