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。 这项研究的基本目标仍然是了解控制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反应的基本适应，也是导致慢性血液感染的主要因素之一。典型的诺氏疟原虫-恒河猴疟疾模型一直是调查的主要焦点。这种猴疟疾模型适用于体外和体内研究，在幼猴体内多次传代(60代)后，表达不同SICA(Schizont感染性细胞凝集)变异抗原表型的诺氏疟原虫H株独特的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。 最近的研究集中于对大型SICAvar基因家族的持续全基因组分析，虽然诺氏疟原虫基因组已经公布(Pain等人；下文)，但仍需要对SICAvar数据进行大量完善，这一工作一直在本实验室进行。在过去的一年里，对感染红细胞的LC-MS/MS分析也提供了Pk1(A+)1+、Pk1(B+)1+和Pk1(C+)1+克隆的表型特征。最后，正在与合作者进行实验，从体内感染和体外适应培养的寄生虫的RNA样本中开发出全面的血液阶段转录组。

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 basic objective of this research continues to be understanding 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 of malaria has been the primary focus of investigations. This simian malaria 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. Recent studies have focused on continued genome wide analyses of the large SICAvar gene family, and while the P. knowlesi genome has been published (Pain et al; below), much refinement of the SICAvar data is still needed and this has been ongoing in this laboratory. In the past year, LC-MS/MS analyses of infected erythrocytes has also provided the phenotypic profile of the Pk1(A+)1+, Pk1(B+)1+ and Pk1(C+)1+ clones. Lastly, experiments are underway with collaborators to develop a comprehensive blood-stage transcriptome from RNA samples from an in vivo infection and in vitro adapted cultured parasites.