EVASION OF ANTIGEN PRESENTATION BY RHESUS CYTOMEGALOVIRUS

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 本提案的主要目标是鉴定和表征巨细胞病毒的体外免疫调节功能，并确定其在体内免疫逃避中的作用。最近完成的RhCMV基因组序列揭示了HCMV中发现的许多免疫调节剂的保守性。其中包括阻止主要组织相容性复合体I类（MHC I）分子将抗原呈递给T细胞的病毒基因。包括我们在内的几个实验室的工作先前发现，US 6家族的四种糖蛋白（US 2，US 3，US 6和US 11）抑制HCMV感染细胞中MHC I的组装和转运。我们证明了RhCMV编码这四种免疫调节剂（Rh 182、Rh 184、Rh 185和Rh 189）中每一种的功能同源物。在这些研究的过程中，我们取得了意想不到的和令人兴奋的发现，RhCMV编码一种额外的机制，该机制在US 6家族蛋白干扰之前的一个步骤中拦截MHC I重链（HC）而不是轻链（β 2 m）的生物合成。这种新的机制，被称为病毒干扰HC表达（VIHCE），迄今尚未在HCMV感染的细胞中观察到。本申请的目的是a）检查MHC I干扰机制对于逃避体内CD 8 + T细胞控制是否重要，B）检查US 6相关和不相关基因在体内免疫逃避中的重要性和c）表征VIHCE的分子机制。 具体目的1：鉴定编码VIHCE的基因。该特定目的的目标是鉴定RhCMV基因组中哪个开放阅读框编码负责VIHCE表型的基因。具体目标2：VIHCE的功能表征。该特定目的的目标是进一步表征在用野生型或VIHCE缺失的RhCMV感染的细胞中的VIHCE机制。具体目标3：MHC I调节剂在建立和维持RhCMV持续感染中的作用。我们将研究恒河猴再感染模型中VIHCE和US 6相关基因对病毒免疫逃避的作用。

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 major goal of this proposal is to identify and characterize cytomegaloviral immunomodulatory functions in vitro and to define their role for immune evasion in vivo. The recent completion of the RhCMV genomic sequence revealed a conservation of many immunomodulators identified in HCMV. Among those are viral genes preventing antigen presentation to T cells by major histocompatibility complex class I (MHC I) molecules. Work in several laboratories, including ours, previously uncovered that four glycoproteins of the US6-family (US2, US3, US6 and US11) inhibit assembly and transport of MHC I in HCMV-infected cells. We demonstrated that RhCMV encodes functional homologues for each of these four immunomodulators, (Rh182, Rh184, Rh185 and Rh189). In the course of these studies we made the unexpected and exciting discovery that RhCMV encodes an additional mechanism which intercepts biosynthesis of MHC I heavy chains (HC), but not light chains (beta2m), at a step that precedes the interference by US6-family proteins. This novel mechanism, termed viral interference with HC expression (VIHCE), has so far not been observed in HCMV-infected cells. The goals of this application are a) to examine whether MHC I interference mechanisms are important for evading CD8+ T cell control in vivo, b) to examine the importance of US6-related and -unrelated genes in immune evasion in vivo and c) to characterize the molecular mechanism of VIHCE. Specific Aim 1: Identification of the gene encoding VIHCE. The goal of this specific aim is to identify which open reading frame in the RhCMV-genome encodes the gene responsible for the VIHCE phenotype. Specific Aim 2: Functional characterization of VIHCE. The goal of this specific aim is to further characterize the VIHCE mechanism in cells infected with wildtype or VIHCE-deleted RhCMV. Specific Aim 3: The role of MHC I modulators for establishment and maintenance of persistent infection by RhCMV. We will examine the role of VIHCE and US6-related genes for viral immune evasion in a re-infection model in rhesus macaques.