A universal malaria T cell vaccine based on HLA-E presentation

摘要 长期以来，疟疾特异的CD8T细胞一直被认为控制着疟疾的肝脏阶段。我们最近展示了 它们还可以杀死感染间日疟原虫的网织红细胞。然而，T细胞靶向抗原 由寄生虫感染细胞上的主要组织相容性复合体(MHC)I类分子在任何阶段呈现 在很大程度上是未知的；知识的缺乏阻碍了合理设计的T细胞的发展- 基于疟疾的疫苗。在初步实验中，我们确定了P. 感染间日疟原虫的网织红细胞。这一分析表明，许多MHC-I结合肽来自于 丰富的看家蛋白，如组蛋白和核糖体蛋白，在 疟原虫物种--当前疫苗策略中没有提出的目标。因此，这一发现创造了 开发泛疟原虫疫苗的独特机会，可将T细胞激发到验证的靶点。出乎意料的是， 在多个供体中发现了几个多肽，而不考虑它们的MHC-单倍型和我们的初步数据 表明这在一定程度上是由于MHC-E上的多肽呈现，MHC-E是一种非多态的MHC-Ib分子。因此，我们 假设MHC-E限制性CD8 T细胞有助于T细胞介导的抗疟疾和 这可以利用基于巨细胞病毒(CMV)的载体进行疫苗设计，这是唯一的平台 它可以被编程来激发MHC-E限制性CD8 T细胞对插入的抗原的反应。这一假设 将使用食蟹猴非人类间日疟原虫灵长类动物模型进行三个特定目标的测试 人间日疟原虫感染样本的验证：在目标1中，我们将确定MHC-E对 间日疟原虫抗原肽对CD8T细胞的呈递及MHC-E靶向在CD8T细胞中的可能作用 对感染的网织红细胞(IRetics)的细胞杀伤。在目标2中，我们将描述间日疟原虫个体的作用 MHC-E限制性CD8 T细胞靶向iRetics的抗原。这将通过确定MHC- 并检测转TCR基因的T细胞靶向iRetics的能力。在……里面 此外，我们还将类似地研究恒河猴MHC-E限制性CD8 T细胞对特定抗原的诱导作用 用基因修饰的恒河猴巨细胞病毒载体(RhCMV)免疫猕猴 MHC-E限制性CD8T细胞。在目标3中，我们将比较基于RhCMV的间日疟原虫疫苗引起的MHC-E或 MHC-Ia限制对选定的、保守的抗原的反应，这取决于它们对P. 食蟹猴在猕猴身上的挑战。具体地说，我们将监测对肝脏阶段的保护， 因肝脏休眠而导致的原发血液期和复发血液期。此协作计划 汇集了不同的专业知识，如果成功，将提供一种高度创新的方法来治疗疟疾 预计将对疫苗研究产生持久影响的疫苗开发。

ABSTRACT Malaria-specific CD8+ T cells have long been known to control the liver stages of malaria. We recently showed that they can also kill reticulocytes infected with Plasmodium vivax. However, the T cell targeted antigens presented by major histocompatibility complex (MHC) class I molecules on parasite-infected cells at any stage are largely unknown; a lack of knowledge that has hampered the development of rationally designed, T cell- based vaccines for malaria. In preliminary experiments we determined the MHC-I peptidome presented on P. vivax-infected reticulocytes. This analysis revealed that many MHC-I-bound peptides are derived from abundant house-keeping proteins such as histones and ribosomal proteins that are highly conserved among Plasmodium species—targets not represented in current vaccine strategies. This discovery thus creates the unique opportunity to develop pan-Plasmodium vaccines eliciting T cells to validated targets. Unexpectedly, several peptides were identified in multiple donors regardless of their MHC-haplotype and our preliminary data show this is in part due to peptide presentation on MHC-E, a non-polymorphic MHC-Ib molecule. We therefore hypothesize that MHC-E-restricted CD8+ T cells contribute to T cell-mediated protection against malaria and that this can be exploited for vaccine design using cytomegalovirus (CMV)-based vectors, the only platform that can be programmed to elicit MHC-E-restricted CD8+ T cell responses to inserted antigens. This hypothesis will be tested in three specific aims using the P. cynomolgi non-human primate model of P. vivax with validation in human P. vivax-infected samples: In Aim 1 we will determine the relative contribution of MHC-E to presentation of P.vivax peptides to CD8+ T cells and investigate a possible role of MHC-E-targeting in CD8+ T cell killing of infected reticulocytes (iRetics). In Aim 2 we will characterize the role of individual P. vivax antigens in MHC-E-restricted CD8+ T cell targeting of iRetics. This will be accomplished by identifying MHC- E/peptide-specific T cell receptors and examining the ability of TCR-transfected T cells to target iRetics . In addition, we will similarly characterize MHC-E-restricted CD8+ T cells elicited to selected antigens in rhesus macaques immunized with genetically modified rhesus cytomegalovirus vectors (RhCMV) that elicit exclusively MHC-E-restricted CD8+ T cells. In Aim 3, we will compare RhCMV-based P. vivax vaccines eliciting MHC-E or MHC-Ia-restricted responses to selected, conserved antigens with respect to their ability to protect against P. cynomolgi challenge in rhesus macaques. Specifically, we will monitor protection against the liver stage, primary blood stage and relapsing blood stage resulting from dormant liver stages. This collaborative program brings together diverse expertise and, if successful, will provide a highly innovative approach to malaria vaccine development that is expected to have a lasting impact on vaccine research.