The H antigen (substance H, O-secretor mucin glycan phenotype) is the common intermediate substrate for the A and B antigens of the ABO blood groups. Its antigenicity is defined by the terminal disaccharide Fucose-Galactose - (α-1-Fuc-(1 → 2)-β-d-Gal-O-R, where R is glycolipid or glycoprotein). Its expression by epithelium is associated with susceptibility to asthma exacerbations. It is formed by the enzyme Galactoside 2-alpha-L-fucosyltransferase 1 and non-functional mutation of its FUT1 gene results in the Bombay blood group which can not express A, B or H antigens and who must not receive blood tranfusions from anyone apart from other Bombay blood group members.
- ↑ Alfaro JA, Zheng RB, Persson M, Letts JA, Polakowski R, Bai Y, Borisova SN, Seto NO, Lowary TL, Palcic MM, Evans SV. ABO(H) blood group A and B glycosyltransferases recognize substrate via specific conformational changes. The Journal of biological chemistry. 2008 Apr 11; 283(15):10097-108.(Link to article – subscription may be required.)
- ↑ Innes AL, McGrath KW, Dougherty RH, McCulloch CE, Woodruff PG, Seibold MA, Okamoto KS, Ingmundson KJ, Solon MC, Carrington SD, Fahy JV. The H antigen at epithelial surfaces is associated with susceptibility to asthma exacerbation. American journal of respiratory and critical care medicine. 2011 Jan 15; 183(2):189-94.(Link to article – subscription may be required.)