ABO blood group antigens (ABO)

ABO blood group antigens are complex carbohydrate structures expressed on the surface of erythrocytes and various other cell types, including endothelial and epithelial cells (UniProt P16442). These antigens are synthesized by specific glycosyltransferases encoded by the ABO gene, which modify the H precursor substance by adding terminal sugar residues: N-acetylgalactosamine for the A antigen and galactose for the B antigen (NIH Gene ID: 28). They are the most significant blood group system in clinical practice because individuals naturally develop antibodies against the antigens they lack, leading to life-threatening immune responses if incompatible blood or organs are introduced (StatPearls: Blood Groups). Beyond their role in transfusion medicine, ABO antigens are involved in cell-cell interactions and have been linked to differential susceptibility to various diseases, including gastric cancer, venous thromboembolism, and certain infectious diseases like malaria (PubMed: 26014468). Therapeutic interventions targeting these antigens include the experimental use of glycosidase enzymes to convert A or B blood types into universal O type by removing the terminal sugars (PubMed: 31182865).

Other names

ABO systemHisto-blood group antigensA antigenB antigenH antigenBlood group ABlood group B

Antibody-mediated agglutination and complement-dependent hemolysis; enzymatic removal of terminal carbohydrate residues to alter immunogenicity (PubMed: 31182865).