Watkins W M, Morgan W T
J Immunogenet. 1976 Feb;3(1):15-27.
Haemagglutination inhibition experiments were carried out with anti-P1, anti-Pk and anti-P sera in an attempt to increase understanding of the chemical, genetical and serological relationships within the P system. The test-substances comprised a glycoprotein with human blood group P1 and Pk activity isolated from sheep hydatid cyst fluid, fragments isolated from the partial acid hydrolysis products of the P1Pk active glycoprotein, glycolipids, monosaccharides and di- and oligo-saccharides of known structure. The trisaccharide alphaGal(1 leads to 4)betaGal(1 leads to 4)GlcNAc isolated from the glycoprotein hydrolysis products, and earlier established as the P1 determinant (Cory et al., 1974), was the only low molecular weight compound that gave strong inhibition with human, rabbit and goat anti-P1 sera. A disaccharide alphaGal(1 leads to 4)Gal, also isolated from the glycoprotein hydrolysis products, failed to react with anti-P1 reagents but inhibited human anti-Pk sera as strongly as the trisaccharide. The glycolipid alphaGal(1 leads to 4)betaGal(1 leads to 4)Glc-Cer (Ceramide trihexoside) and other oligosaccharides containing alphaGal(1 leads to 4)Gal at the non-reducing terminal were also strong inhibitors of anti-Pk sera. Oligosaccharides with terminal alpha-galactosyl residues joined in other positional linkages gave definite, although less strong, inhibition. The inhibition results suggest a close structural relationship between the P1 and Pk determinants and indicate that the specificity of anti-Pk sera is less closely delineated than that of anti-P1. Human anti-P sera differed markedly from anti-P1 and anti-Pk and were not inhibited by any of the compounds containing alpha-galactosyl residues. The glycolipid betaGalNAc(1 leads to 3)alphaGal(1 leads to 4)betaGal(1 leads to 4)Glc-Cer (globoside) strongly inhibited the anti-P sera. The inhibition of anti-Pk and anti-P sera by ceramide trihexoside and globoside, respectively, confirms the observations of Naiki & Marcus (1974) and supports their conclusions that Pk is the precursor of P. The genetic relationship of the P1 antigen to P and Pk is not clear but biosynthetic pathways are discussed that might explain the absence of P1, Pk and P antigens in individuals of the p phenotype.
进行了血凝抑制试验，使用抗P1、抗Pk和抗P血清，旨在增进对P系统内化学、遗传和血清学关系的理解。测试物质包括从羊包虫囊肿液中分离出的具有人血型P1和Pk活性的糖蛋白、从P1Pk活性糖蛋白的部分酸水解产物中分离出的片段、糖脂、单糖以及结构已知的二糖和寡糖。从糖蛋白水解产物中分离出的三糖αGal(1→4)βGal(1→4)GlcNAc，先前已确定为P1决定簇（科里等人，1974年），是唯一能与人、兔和山羊抗P1血清产生强烈抑制作用的低分子量化合物。同样从糖蛋白水解产物中分离出的二糖αGal(1→4)Gal，不与抗P1试剂反应，但对人抗Pk血清的抑制作用与三糖一样强。糖脂αGal(1→4)βGal(1→4)Glc-Cer（神经酰胺三己糖苷）和其他在非还原末端含有αGal(1→4)Gal的寡糖也是抗Pk血清的强抑制剂。具有以其他位置连接方式连接的末端α-半乳糖基残基的寡糖产生了明确的抑制作用，尽管强度较小。抑制结果表明P1和Pk决定簇之间存在密切的结构关系，并表明抗Pk血清的特异性不如抗P1血清那样明确界定。人抗P血清与抗P1和抗Pk血清明显不同，且不受任何含有α-半乳糖基残基的化合物抑制。糖脂βGalNAc(1→3)αGal(1→4)βGal(1→4)Glc-Cer（红细胞糖苷脂）强烈抑制抗P血清。神经酰胺三己糖苷和红细胞糖苷脂分别对抗Pk和抗P血清的抑制作用，证实了内木和马库斯（1974年）的观察结果，并支持了他们关于Pk是P的前体的结论。P1抗原与P和Pk的遗传关系尚不清楚，但讨论了可能解释p表型个体中缺乏P1、Pk和P抗原的生物合成途径。
