Structures of Capsular Polysaccharide Serotypes 35F and 35C of Streptococcus pneumoniae Determined by Nuclear Magnetic Resonance and Their Relation to Other Cross-Reactive Serotypes
Structures of Capsular Polysaccharide Serotypes 35F and 35C of Streptococcus pneumoniae Determined by Nuclear Magnetic Resonance and Their Relation to Other Cross-Reactive Serotypes
复制标题
核磁共振测定肺炎链球菌荚膜多糖血清型35F和35C的结构及其与其他交叉反应血清型的关系
DOI：
10.1128/jb.00207-15
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发表时间：
2015-09-01
影响因子：
3.2
通讯作者：
Yang, Jinghua
中科院分区：
文献类型：
--
作者：
Bush, C. Allen;Cisar, John O.;Yang, Jinghua
肺炎链球菌被膜多糖(CPSS)的结构对于确定CPS血清型之间的抗原性和亲缘关系是必不可少的。已知构成CPS血清群35的四个血清型(即35F、35A、35B和35C型)与遗传相关的20、29、34、42或47F型发生交叉反应。CPS血清型35A(CPS35A)和CPS35B的结构已知，CPS35F和CPS35C的结构未知。在本研究中，CPS35F和CPS35C的血清型通过高分辨率核磁共振波谱和糖基组成分析进行了表征，揭示了以下重复单元结构：其中OAC表示O-乙酰化。重要的是，产生35群血清的免疫血清型CPS35F比35群的其他成员更接近于CPS34和CPS47F。此外，CPS35C既不同于CPS35F，也不同于CPS35B，但与CPS35A密切相关，与脱氧乙酰化的CPS42相同。这些发现提供了CPS血清组35成员和其他交叉反应血清型之间存在的结构和遗传关系的全面看法。重要性诊断兔抗血清与肺炎链球菌荚膜多糖血清型的交叉反应一般仅限于同一血清组的成员。然而，例外情况确实发生，最明显的是在一组非疫苗血清型中，包括血清组35的成员(即35F、35A、35B和35C型)和其他遗传相关类型。目前确定的肺炎链球菌血清型35F和35C的结构完成了血清组35的结构特征，从而首次全面描述了该血清组的不同成员如何相互关联以及如何与29、34、42和47F型相关。这些血清型的结构和遗传特征表明，存在三个不同的荚膜多糖亚群，推测是通过在人类宿主中进行免疫选择而出现的。
ABSTRACT The structures of Streptococcus pneumoniae capsular polysaccharides (CPSs) are essential for defining the antigenic as well as genetic relationships between CPS serotypes. The four serotypes that comprise CPS serogroup 35 (i.e., types 35F, 35A, 35B, and 35C) are known to cross-react with genetically related type 20, 29, 34, 42, or 47F. While the structures of CPS serotype 35A (CPS35A) and CPS35B are known, those of CPS35F and CPS35C are not. In the present study, the serotypes of CPS35F and CPS35C were characterized by high-resolution heteronuclear magnetic resonance (NMR) spectroscopy and glycosyl composition analyses to reveal the following repeat unit structures: where OAc indicates O-acetylated. Importantly, CPS35F, the immunizing serotype for the production of group 35 serum, more closely resembles CPS34 and CPS47F than other members of serogroup 35. Moreover, CPS35C is distinct from either CPS35F or CPS35B but closely related to CPS35A and identical to de-O-acetylated CPS42. The findings provide a comprehensive view of the structural and genetic relations that exist between the members of CPS serogroup 35 and other cross-reactive serotypes. IMPORTANCE Cross-reactions of diagnostic rabbit antisera with Streptococcus pneumoniae capsular polysaccharide serotypes are generally limited to members of the same serogroup. Exceptions do, however, occur, most notably among a group of nonvaccine serotypes that includes the members of serogroup 35 (i.e., types 35F, 35A, 35B, and 35C) and other genetically related types. The presently determined structures of S. pneumoniae serotypes 35F and 35C complete the structural characterization of serogroup 35 and thereby provide the first comprehensive description of how different members of this serogroup are related to each other and to types 29, 34, 42, and 47F. The structural and genetic features of these serotypes suggest the existence of three distinct capsular polysaccharide subgroups that presumably emerged by immune selection in the human host.