Immunochemical characterization of native polysaccharides from group B streptococcus: the relationship of the type III and group B determinants.
Immunochemical characterization of native polysaccharides from group B streptococcus: the relationship of the type III and group B determinants.
复制标题
B 组链球菌天然多糖的免疫化学特征：III 型和 B 组决定簇的关系。
DOI：
10.4049/jimmunol.121.3.1096
复制
发表时间：
1978
影响因子：
4.4
通讯作者：
C. Baker
中科院分区：
文献类型：
--
作者：
D. Kasper;D. K. Goroff;C. Baker
通过用EDTA缓冲液洗涤细胞或用冷的10%TCA提取，从在不同的酸暴露条件下生长的B组链球菌的III型菌株中纯化三种多糖。用pH滴定仪缓冲的培养基中生长的细胞的提取导致1.2 × 106道尔顿的多糖抗原，其仅具有III型血清学特异性。用EDTA从在酸积累的培养基中生长的细胞中提取的抗原具有约600，000的分子大小，并且证明了III型和B型血清学活性。用TCA提取的抗原具有约500，000的分子大小，并且也与III型和B型血清反应。化学研究表明，所有三种多糖含有不同浓度的半乳糖，葡萄糖，葡萄糖胺和唾液酸。只有TCA抗原含有鼠李糖。TCA抗原的乙醇分级分离允许III型与B组血清学反应性分离。然而，该方法未能分离EDTA-非pH滴定抗原的两个决定簇。其他物理、化学和免疫学方法同样无法分离这两种决定因素。EDTA-pH滴定抗原的轻度水解暴露了与甲酰胺提取的B组抗原免疫学相同的决定簇。这些研究以及电子显微镜和亲和层析表明，两个决定簇存在于天然多糖抗原的III型，B组链球菌。一个是表面荚膜类型特异性决定簇，其在最天然的状态下掩盖了第二个决定簇，一个常见的B组决定簇。
定量沉淀抑制研究证实，l-鼠李糖是甲酰胺提取的B抗原的免疫显性糖。没有单糖抑制EDTA-非pH滴定抗原上的交叉反应决定簇。尽管有这种观察结果，但已证明甲酰胺提取的B抗原和EDTA-非pH滴定的抗原均沉淀具有相同特异性的抗体。
Three polysaccharides were purified from a type III strain of Group B Streptococcus grown under conditions varying in exposure to acid by washing the cells with an EDTA buffer or extracting with cold 10% TCA. Extraction of cells grown in a medium buffered with a pH titrator resulted in a polysaccharide antigen of 1.2 × 106 daltons having only type III serologic specificity. The antigen extracted with EDTA from cells grown in a medium where acid accumulated had a molecular size of approximately 600,000, and demonstrated both type III and group B serologic activity. The antigen extracted with TCA had a molecular size of approximately 500,000 and also reacted with type III and group B sera. Chemical studies revealed that all three polysaccharides contained varying concentrations of galactose, glucose, glucosamine, and sialic acid. Only the TCA antigen contained rhamnose. Alcohol fractionation of the TCA antigen allowed separation of type III from group B serologic reactivity. However, this method failed to separate the two determinants of the EDTA-non-pH titrated antigen. Other physical, chemical, and immunologic methods similarly failed to separate these two determinants. Mild hydrolysis of the EDTA-pH-titrated antigen exposed a determinant immunologically identical to the formamide-extracted group B antigen. These studies as well as electron microscopy and affinity chromatography demonstrated that two determinants exist on the native polysaccharide antigen of type III, Group B Streptococcus. One is the superficial capsular type specific determinant, which in the most native state masks the second determinant, a common group B determinant.
Quantitative precipitation inhibition studies confirmed that l-rhamnose was the immunodominant sugar for the formamide-extracted B antigen. No monosaccharide inhibited the cross-reactive determinant on the EDTA-non pH titrated antigen. Despite this observation, both the formamide-extracted B antigen and the EDTA-non pH titrated antigen were demonstrated to be precipitating antibodies of identical specificity.