MOLECULAR BASIS OF ANTIGENIC VARIATION ON MALARIA

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 本研究的目的是集中在疟原虫变异抗原基因表达的分子机制。抗原变异是逃避宿主保护性免疫应答的基本适应，并且是促成慢性血液感染建立的主要因素之一。经典的诺氏疟原虫-恒河猴模型适用于体外和体内研究，并且在诱导的顺序转换后表达不同SICA（裂殖体感染细胞凝集）变体抗原表型的诺氏疟原虫H株的独特稳定克隆可以在幼稚恒河猴中多次体内传代（60代）后保持。这些同基因克隆系为研究克隆抗原变异的细胞和遗传机制提供了一个特殊的工具。今年，我们进行了几项新的体内转换实验，并使用LC-MS/MS，生物信息学工具和分子生物学测试表征了新的转换SICA表型。还采取了几种方法来产生针对所定义的SICA蛋白的特异性抗体，并在与SICA蛋白的运输和转换事件相关的实验中使用这些试剂。我们还与英国的桑格中心建立了新的合作关系，进行NextGen和RNAseq实验，以完善诺氏疟原虫基因组数据库。这是我们发表的关于重新定义的SICAvar原型基因和蛋白质的报告的后续行动，该报告强调需要进一步关注Pk基因组数据的关闭。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The objectives of this research are focused on the molecular mechanisms that govern variant antigen gene expression in Plasmodium. Antigenic variation is a fundamental adaptation to evade a host protective immune response and is one of the major factors contributing to the establishment of chronic blood infections. The classic P. knowlesi-rhesus monkey model is amenable to both in vitro and in vivo studies and unique stable clones of the P. knowlesi H strain expressing distinct SICA (Schizont Infected Cell Agglutination) variant antigen phenotypes after induced sequential switchings can be maintained after numerous in vivo passages (60 generations) in naive rhesus monkeys. These isogenic clonal lines provide a special tool for studies of the cellular and genetic mechanisms underlying clonal antigenic variation. This year, we performed several new in vivo switch experiments and characterized the new switched SICA phenotypes using LC-MS/MS, bioinformatic tools and molecular biological tests. Several approaches were also undertaken to generate specific antibodies to defined SICA proteins and use these reagents in experiments relating to trafficking of the SICA proteins and switch events. We also established new collaborations with the Sanger Center in the UK to perform NextGen and RNAseq experiments to refine the P. knowlesi genome database. This was much welcomed as a follow-up to a report we published on the redefined SICAvar prototype gene and protein, which emphasizes the need for further attention on the closure of the Pk genome data.