EVOLUTION OF GROUP A STREPTOCOCCI

描述（改编自申请人的摘要）： A组化脓性链球菌的结构将通过多重 基因座序列分型（MLST）的全球代表性样本600 菌株使用7个不同的基因座。 来自另外200个染色剂的数据将 在本项目开始之前，已获得其他资金。 将选择276个细菌进行MLST，以代表emm的多样性 序列分型（emmst），其中146种类型是目前已知的，并且来自作为 尽可能多的来源和时间段。 额外的emmst将 执行。 数据将通过聚类分析的差异进行分析， 等位基因，关联指数和系统发育树，以确定如何 重组的作用很重要。 speA和speC等位基因 个别菌株亦会接受测试。 的人口分布 将比较MLST检测的M蛋白和管家基因， 确定它们之间的关联程度。 这些分析将检验这一假设 M蛋白导致了emm模式A-C中更多的离散菌株 亚群比emm模式D菌株。 第二个假设是，在emm模式E菌株中，两组多态性 抗原（EMM加SOF）引起免疫应答， 在这些抗原中不重叠的菌株（Gupta的两个表位模型）。 到 为了验证这一假设，将产生多克隆抗血清， 重叠的重组SOF多肽和类型特异性位点 通过确定哪个重叠区域在不同的区域中起反应， 重组肽。 该类型特异性区域将从所有 E型分离株。 将使用双向列联表确定 EMMST和SOF等位基因的组合是否如通过 假设或随机。 人IgG亚类，伊加， 将通过Southern杂交筛选纤溶酶原和纤维蛋白原， 将与上述类似地分析数据。 另外325个菌株将 根据上述分析的结果选择短期分析 流行病学从定义的情况。 将进行相同的分析， 与第一组菌株。 最后，将通过竞争性分析对emm和sof产品的抗血清进行分析， 抑制、调理作用和抑制配体与 细菌 不同M蛋白之间的交叉反应性将是相关的 系统发育分析和免疫选择模型。 将获得额外的抗血清，并在免疫后进行检测， EMMST和SOF基因产物的型特异性表位。 这些血清将是 测试以确定应变结构是否由 EMM和SOF基因产物的免疫原性。

DESCRIPTION (Adapted from the Applicant's Abstract): The population genetic structure of group A Streptococcus pyogenes will be investigated by multi locus sequence typing (MLST) of a globally representative sample of 600 strains using 7 distinct gene loci. Data from an additional 200 stains will have been obtained with other funding prior to the beginning of this project. 276 bacteria will be selected for MLST to represent the diversity of emm sequence typing (emmst), of which 146 types are currently known, and from as diverse sources and time periods as possible. Additional emmst will be performed. The data will be analyzed by cluster analysis of differences in alleles, indices of association, and phylogenetic trees to determine how important the role of recombination is. The speA and speC alleles of the individual strains will also be tested. The population distributions of the M-protein and the housekeeping genes tested by MLST will be compared to determine how well they correlate. These analyses will test the hypothesis that the M protein has led to more discrete strains in the emm pattern A-C subpopulation than in the emm pattern D strains. A second hypothesis is that in emm pattern E strains, two sets of polymorphic antigens (emm plus sof) elicit immune responses and immunity has selected strains that do not overlap in these antigens (Gupta's two epitope model). To test this hypothesis, polyclonal antisera will be generated against overlapping recombinant sof polypeptides and the type-specific sites for binding mapped by determining which overlapping region reacts in the different recombinant peptides. That type-specific region will be sequenced from all pattern E isolates. Two-way contingency tables will be used to determine whether the combinations of emmst and sof alleles are as predicted by the hypothesis or random. Emm-based binding sites for human IgG subclasses, IgA, plasminogen and fibrinogen will be screened by Southern hybridization and the data will be analyzed similarly to above. An additional 325 strains will then be chosen based on the results from the above analyses to analyze short term epidemiology from defined situations. The same analyses will be performed as with the first set of strains. Finally, the antisera to emm and sof products will be analyzed by competitive inhibition, opsonization and for inhibition of binding of ligands to the bacteria. Cross 0- reactivity between different M proteins will be correlated with the phylogenetic analyses and models for selection by immunity. Additional antisera will be obtained and tested after immunization with type-specific epitopes of emmst and sof gene products. These sera will be tested to determine whether strain structure is determined by the immunogenicity of the emm and sof gene products.