MOLECULAR BASIS OF ANTIGENIC VARIATION ON MALARIA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 本研究的目标集中在控制疟原虫变异抗原基因表达的分子机制上。抗原变异是逃避宿主保护性免疫反应的基本适应，也是导致慢性血液感染的主要因素之一。经典的诺氏疟原虫-恒河猴模型适合于体外和体内研究，在幼稚的恒河猴体内多次传代(60代)后，表达不同SICA(Schizont感染性细胞凝集)变异抗原表型的唯一稳定克隆仍能保持不变。这些等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种特殊的工具。我们假设，克隆表型的研究为理解体内抗原变异的调节提供了洞察力。 今年，我们发表了一份关于重新定义的SICAvar原型基因和蛋白质的重要报告，强调需要进一步关注PK基因组数据的关闭。我们还利用蛋白质组学(LC-MS/MS)、实时RT-PCR和Northern印迹实验获得了确定的数据，这些实验定义了经典的诺诺氏菌Pk1(A+)1+、Pk1(B+)1+和Pk1(C+)1+(即Sica+)克隆产生的主要转录和蛋白质，并显示出在SICA克隆中的强烈下调。从体内恒河猴感染和体外适应的寄生虫收集的RNA样本中，还在与合作者和一份手稿一起准备一个全面的诺氏疟原虫血液期转录组。蛋白质组数据也正在生成，并与转录组进行比较，SICA表达和其他假设正在测试中。 我们还发表了一篇综述，强调诺氏疟原虫不仅作为一个模型系统，而且作为一种寄生虫的重要性，最近显示它会导致数百例人类疟疾病例。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 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. We hypothesized that studies of the clonal phenotypes provide insights towards understanding the regulation of antigenic variation in vivo. This year, we published an important report on the redefined SICAvar prototype gene and protein, which emphasizes the need for further attention to the closure of the Pk genome data. We have also produced definitive data using proteomics (LC-MS/MS), real time RT-PCR and northern blot experiments defining the predominant transcripts and proteins produced by the classical P. knowlesi Pk1(A+)1+, Pk1(B+)1+ and Pk1(C+)1+ (i.e. SICA+) clones and show strong downregulation in the SICA- clones. Analyses are also underway with collaborators and a manuscript in preparation on a comprehensive P. knowlesi blood-stage transcriptome from RNA samples collected from an in vivo rhesus infection and in vitro adapted parasites. Proteomic data is also being generated, and compared with the transcriptome, with SICA expression and other hypotheses being tested. We also published a review emphasizing the importance of P. knowlesi not only as a model system, but also as a parasite shown recently to cause hundreds of cases of malaria in humans.