EVOLUTION OF GROUP A STREPTOCOCCI

描述(改编自申请者摘要)：群体遗传 A组化脓性链球菌的结构将进行多项研究 具有全球代表性的600个样本的基因座序列分型 菌株使用7个不同的基因座。来自另外200个污渍的数据将 在这个项目开始之前，已经用其他资金获得了。 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种是目前已知的类型，来自AS 尽可能多样化的来源和时间段。额外的Emmst将是 已执行。数据将通过聚类分析进行差异分析 等位基因、关联指数和系统发育树，以确定 重要的是重组的作用是。猪的SPEA和SPEC等位基因 个别菌株也将接受测试。中国人口的分布 M-蛋白和MLST检测的看家基因将与 确定它们之间的关联程度。这些分析将检验这一假设 M蛋白导致了更多分离的EMM模式A-C菌株 亚群高于EMM型D株。 第二种假设是，在E型EMM菌株中，两组多态 抗原(emm加sof)可激发免疫反应，免疫已选定 在这些抗原中不重叠的菌株(古普塔的双表位模型)。至 验证这一假设，多克隆抗血清将针对 重叠的重组sOF多肽及其类型特异性位点 通过确定哪个重叠区域在不同的 重组多肽。该类型特定区域将从所有 模式E分离。将使用双向列联表来确定 Emmst和sof等位基因的组合是否如 假设或随机。基于EMM的人免疫球蛋白亚类，IgA， 纤溶酶原和纤维蛋白原将通过Southern杂交和 数据的分析方法与上面类似。届时将再增加325个菌株 根据上述分析的结果选择进行短期分析 特定情况下的流行病学。将执行相同的分析，如 第一组菌株。 最后，对emm和sof产品的抗血清进行竞争性分析。 抑制、调理和抑制配体与 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。 在免疫后将获得更多的抗血清并进行检测 Emmst和sof基因产物的类型特异性表位。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.