Coligan J E, Fraser B A, Kindt T J
Prog Clin Biol Res. 1978;23:601-12.
Acid hydrolysis of streptococal Group C polysaccharide yields a disaccharide, 3-O-alpha-N-acetylgalactosaminosyl-N-acetylgalactosamine (3-O-alpha-GalNAc-GalNAc) which expresses Group C antigenic activity. This disaccharide, which exists as a side chain in the intact polysaccharide, can completely inhibit the binding between Group C polysaccharide and most Group C antibodies, indicating that this unit is the immunodominant feature of the intact polysaccharide. The alpha anomeric configuration and N-acetylation are required for the expression of the antigenic activity by the haptenic disaccharide. Also obtained from the acid hydrolysis of the Group C polysaccharide are rhamnose oligosaccharides with structural identity to the Group A-variant polysaccharide and with Group A-variant antigenic activity. It is inferred from these data that the Group A-varient polysaccharide structure is the core unit of the Group C polysaccharide. The nature of the immunologic crossreactivity between the Forssman glycolipid and Group C polysaccharide, which possess identical nonreducing terminal digalactosamine units, was investigated. Rabbit anti-Group C antibodies bound the Forssman glycolipid with approximately the same affinity as 3-O-alpha-GalNAc-GalNAc and were capable of mediating lysis of sheep red blood cells (SRBC). Antibody fractions isolated from anti-sheep hemolysin were likewise able to bind Group C polysaccharide. The heterologous reactions were in most assay systems weaker than reactions with the immunizing antigen.
C群链球菌多糖的酸水解产生一种二糖，即3 - O-α - N - 乙酰半乳糖胺基 - N - 乙酰半乳糖胺（3 - O-α - GalNAc - GalNAc），其具有C群抗原活性。这种二糖在完整多糖中以侧链形式存在，能完全抑制C群多糖与大多数C群抗体之间的结合，表明该单元是完整多糖的免疫显性特征。半抗原二糖表达抗原活性需要α异头构型和N - 乙酰化。从C群多糖的酸水解产物中还获得了与A群变异多糖结构相同且具有A群变异抗原活性的鼠李糖寡糖。从这些数据推断，A群变异多糖结构是C群多糖的核心单元。研究了福斯曼糖脂与C群多糖之间免疫交叉反应的性质，它们具有相同的非还原末端二半乳糖胺单元。兔抗C群抗体以与3 - O-α - GalNAc - GalNAc大致相同的亲和力结合福斯曼糖脂，并能够介导绵羊红细胞（SRBC）的裂解。从抗绵羊溶血素中分离出的抗体组分同样能够结合C群多糖。在大多数检测系统中，异源反应比与免疫抗原的反应弱。
