Conceptual Onset of Xenotransplantation from ABO Blood Type-Incompatible Organ Allotransplantation

Although regular AB(H) blood group system depicts non-SA-containing erythrocyte differentiation, another example of the Neu5Ac-attached to specific antigens is so-called human blood group MN, raised by genetic variations in the N-terminal regions of glycophorin in RBCs, which yield different and small O-linked sialylation from each individual [1, 2]. Such variations in the antigens also produce the different sialylglycans and consequently generate the specific binding antibodies against human RBCs to affect failure during blood transfusion. Similarly, some antibodies against other blood groups are also considered [3]. For example, the M and N blood group antigens of GPA consist of Siaα2,3Gal- and Siaα2,6GalNAc- residues, linked to O-glycan saccharides. These two M and N blood group antigens are bound by M/N-specific antibodies. The GPA-M and GPA-N antigens are easily confirmed by M-specific and N-specific Mab bindings. The GPAs with SA-Gal called GPA2,3 can be produced by asialoGPAs resialylation reaction using α2,3Sia-transferase. The GPAs with GalNAc-linked Sia (GPA2,6) are also produced, indicating the distinct presence of only one of two SA residues linked to Gal or GalNAc in the epitope [4].