Defining astrovirus-specific T cell responses

项目摘要/摘要 人类星状病毒(HAstV)是引起儿童胃肠炎的全球性原因，并可引起传播 免疫受损宿主的感染。血清阳性研究表明，几乎所有人都感染HAstV。 童年。尽管HASTV具有临床重要性，但对其研究严重不足，部分原因是缺乏良好的- 定义了小动物模型。小鼠星状病毒(MuAstV)，具有大量的基因组和表型 HAstV的特征，在免疫缺陷模型中导致慢性感染，并已开始提供重要的 对ASTV体内致病的先天免疫和获得性免疫调节的洞察。初步数据显示， CD8+T细胞对清除慢性muAstV至关重要。然而，到目前为止，功能和表型特征 对于HAstV和muAstV，CD8+T细胞的反应仍未确定。此外，特定的病毒 HAstV和muAstV以CD8+T细胞为靶点的表位尚待确定。 免疫优势CD8+T细胞表位的定义将有助于ASTV特异性T细胞的鉴定 细胞在体内发挥功能，并揭示关键的病毒表位，为未来的疫苗和细胞治疗提供靶点。重叠 多肽文库将用于免疫优势的muAstV CD8+T细胞表位的体外筛选 建立了方案，目标是开发MHC I类多肽四聚体来跟踪muAstV特异性CD8+ T细胞。两个表型截然不同的muAstV菌株，一个会引起急性自限性感染，另一个会引起急性自限性感染 在免疫活性小鼠中引起慢性感染，将被用来定义效应器和记忆muAstV- 跨多个组织的特定CD8+T细胞表型和功能。这些研究将在 建立活体小鼠模型，将揭示功能不佳的CD8+T细胞反应是否有助于 一些病毒株的清除受损。最后，来自捐赠者的人外周血单核细胞 携带与HAstV保护相关的MHC I类等位基因将被用于识别免疫显性 HAstV CD8+T细胞表位，允许开发四聚体来表征HAstV特异性CD8+T细胞 具有这种常见等位基因的各种捐赠者的表型。 这些研究非常适合R21赠款机制，因为它们涉及制定关键的 用于免疫学研究的工具，使用尚未应用于ASTV的方法。完成这项工作 该提案将提供对抗AstV的细胞免疫反应的关键见解，并开发四聚体 用于未来确定自然感染和疫苗接种后T细胞反应的试剂。此外， 已确定的免疫优势表位将成为疫苗和细胞治疗的重要靶点。 这些临床上重要的肠道病毒病原体。

PROJECT SUMMARY/ABSTRACT Human astroviruses (HAstVs) are a global cause of pediatric gastroenteritis, and can cause disseminated infection in immunocompromised hosts. Seroprevalence studies indicate almost universal HAstV infection during childhood. Despite their clinical importance, HAstVs are highly understudied in part due to the lack of a well- defined small animal model. Murine astrovirus (muAstV), which shares numerous genomic and phenotypic features with HAstVs, causes chronic infection in immunodeficient models and has begun to provide important insights into innate and adaptive immune regulation of AstV pathogenesis in vivo. Preliminary data indicates that CD8+ T cells are critical for clearance of chronic muAstV. However, to date functional and phenotypic features of the CD8+ T cell response remain uncharacterized for both HAstV and muAstV. Further, the specific viral epitopes targeted by CD8+ T cells remain to be delineated for both HAstV and muAstV. The definition of immunodominant CD8+ T cell epitopes will facilitate characterization of AstV-specific T cell functions in vivo and reveal key viral epitopes to target for future vaccines and cellular therapies. Overlapping peptide libraries will be used for ex vivo screening of immunodominant muAstV CD8+ T cell epitopes by well- established protocols, with the goal of developing MHC class I peptide tetramers to track muAstV-specific CD8+ T cells. Two phenotypically-distinct muAstV strains, with one causing acute self-limited infection and the other causing chronic infection in immunocompetent mice, will be leveraged to define effector and memory muAstV- specific CD8+ T cell phenotypes and functionality across multiple tissues. These studies, to be conducted in established in vivo mouse models, will reveal whether functionally suboptimal CD8+ T cell responses contribute to impaired clearance of some viral strains. Finally, human peripheral blood mononuclear cells from donors carrying an MHC class I allele associated with protection from HAstV will be used to identify immunodominant HAstV CD8+ T cell epitopes, permitting development of tetramers to characterize HAstV-specific CD8+ T cell phenotypes across a variety of donors with this common allele. These studies are highly appropriate for the R21 grant mechanism, as they involve development of critical tools for immunological studies using methods that have not yet been applied towards AstVs. Completion of this proposal will both provide key insights into the cellular immune response against AstVs and develop tetramer reagents to be used for future definition of T cell responses following natural infection and vaccination. Further, immunodominant epitopes identified will represent important targets for vaccines and cellular therapies against these clinically important enteric viral pathogens.