Moulds J J, Dahr W
Gamma Biologicals, Inc., Houston, Texas.
Immunol Ser. 1989;43:713-41.
Human red blood cell membranes contain four sialic acid-rich glycoproteins, denoted as glycophorins (GPs), that carry the antigens of the MNSs and Gerbich (Ge) blood group systems. The MNSs locus corresponds to two related and adjacent genes that encode the polypeptide sequences of two of these molecules: GP A and GP B. The structural differences between the major polymorphic antigens M and N or S and s are determined by amino acid heterogeneities within the glycosylated NH2-terminal domain of GP A or GP B, respectively. Because the NH2-terminal 26 residues of GP B are identical with those of GP A possessing blood group N specificity, the former molecule carries an additional N antigen, denoted as 'N'. Apart from the major antigens, GP A and GP B carry several high- or low-frequency receptors that are encoded by the MNSs locus. Additional alleles are apparently silent or produce GP A-GP B hybrid molecules. The Ge locus is similar to the MNSs locus in that it appears to correspond to the adjacent genes encoding the polypeptide chains of GP C and GP D. However, the Ge system does not include antigens that are polymorphic in Caucasoids. Because all GPs are heavily glycosylated, oligosaccharides, in addition to protein, are involved in antigens of the MNSs and Ge systems. The carbohydrate units on all GPs account for additional antigens that are not part of the MNSs or Ge systems.
人类红细胞膜含有四种富含唾液酸的糖蛋白，称为血型糖蛋白（GPs），它们携带MNSs和杰尔拜克（Ge）血型系统的抗原。MNSs基因座对应于两个相关且相邻的基因，它们编码其中两种分子的多肽序列：GPA和GPB。主要多态性抗原M和N或S和s之间的结构差异分别由GPA或GPB糖基化NH2末端结构域内的氨基酸异质性决定。由于GPB的NH2末端26个残基与具有N血型特异性的GPA相同，所以前一种分子携带额外的N抗原，称为“N”。除了主要抗原外，GPA和GPB还携带几种由MNSs基因座编码的高频或低频受体。其他等位基因显然是沉默的，或者产生GPA - GPB杂交分子。Ge基因座与MNSs基因座相似，因为它似乎对应于编码GPC和GPD多肽链的相邻基因。然而，Ge系统不包括在白种人中具有多态性的抗原。由于所有的GPs都高度糖基化，除了蛋白质外，寡糖也参与了MNSs和Ge系统的抗原形成。所有GPs上的碳水化合物单元构成了不属于MNSs或Ge系统的额外抗原。
