Genetic basis of secondary lymphoid organ protection after virus infection

 描述(由申请人提供)：MHC I类DK介导对小鼠巨细胞病毒(MCMV)的遗传耐药性。这种耐药效应需要特定的NK细胞亚群，以抑制性NK受体Ly49G2为标志，防止病毒传播。该提案中的初步数据揭示了一种主要的遗传修饰物，暂时命名为Cmv5，具有依赖DK的病毒抗性。Cmv5的基因图谱位于MHC附近，但在MHC的远端。初步结果表明，它还能调节MCMV感染后小鼠脾内次级淋巴器官结构(SLO)的保护和NK细胞的增殖。目前尚不清楚Cmv5脾对感染的韧性是如何调节的，不同的等位基因如何不同地影响组织病理学结果，或者遗传效应是否通过造血细胞、非造血细胞或两者兼而有之。Cmv5的峰值遗传图谱位置与编码已知调节炎症的分子的Trem/Trem样基因簇一致。据预测，Cmv5通过保护脾SLO结构和通过扩大具有活性的NK细胞来介导特定的病毒清除来加强病毒清除。一个长期目标是识别Cmv5，并研究自然选择的等位基因如何改变其基本生物学功能，并进一步塑造免疫反应、炎症和疾病结果。病毒感染后保护SLO结构和调节坏死和NK细胞聚集的遗传学基础尚不清楚。Cmv5基因突变的小鼠将被用来探索淋巴样结构、NK细胞聚集和天然病毒免疫之间的遗传关系。将研究Cmv5在应对病毒感染时修复/再生生物学的调节。由于TREM与位置基因作图数据、外显子序列分析以及它们调节炎症的倾向有关，因此也将研究TREM/TREM样分子在病毒诱导的炎症和病毒清除中的可能作用。提出了两个具体目标来解决长期目标。目的1探讨巨细胞病毒感染后Cmv5基因位点依赖的次级淋巴器官(SLO)结构保护和脾NK细胞聚集的细胞学基础。据预测，Cmv5可以保护脾红髓和白髓区域的基质细胞。因此，AIM1研究了基质细胞和它们释放的细胞因子之间的关系，以及它们支持和/或再生SLO结构的能力，这可能是进一步调节白细胞募集和保留所必需的。目的2对MCMV感染后SLO结构的TREM表达、功能和支持进行精确的Cmv5定位和分析。据预测，小鼠Chr-17上的16-Mb间隔跨越Cmv5基因，该基因调控病毒感染后脾中SLO结构、组织坏死和NK细胞的扩张。由于该基因座跨越编码调节炎症所需的髓系衍生蛋白的TREM/TREM样基因簇，进一步的预测是，一个或多个TREM/TREM样蛋白调节SLO的结构/功能、NK细胞的扩张和病毒免疫的增强。

 DESCRIPTION (provided by applicant): MHC class I Dk mediates genetic resistance to murine cytomegalovirus (MCMV). The resistance effect requires a specific subset of NK cells marked by an inhibitory NK receptor, Ly49G2, that protects against viral spread. Preliminary data in the proposal has revealed a major genetic modifier, provisionally designated Cmv5, of Dk- dependent virus resistance. Cmv5 was genetically mapped nearby, but distal to the MHC. Preliminary results show that it also regulates protection of secondary lymphoid organ structure (SLO) and expansion of NK cells in spleen soon after MCMV infection. It is not known how Cmv5 spleen resilience to infection is regulated, how distinct alleles differently affect histopathological outcomes or if the genetic effect manifests through hematopoietic cells, non-hematopoietic cells or both. The peak genetic map position for Cmv5 coincides with the Trem/Trem-like gene cluster that encodes molecules known for regulating inflammation. Cmv5 is predicted to intensify virus clearance by protecting spleen SLO structure and by expanding competent NK cells to mediate specific virus clearance. A long-term goal is to identify Cmv5 and investigate how naturally selected alleles alter its basic biological functions and further shape immune responsiveness, inflammation and disease outcomes. A genetic basis for protection of SLO structure and regulation of necrosis and NK cell accumulation after virus infection is unknown. Cmv5-disparate mice will be used to explore the genetic relationship between lymphoid structure, NK cell accumulation and innate viral immunity. Cmv5 regulation of the biology of repair/regeneration in response to virus infection will be studied. Inasmuch as Trems are implicated by positional genetic mapping data, exome sequence analysis and for their proclivity to regulate inflammation, a possible role for Trem/Trem-like molecules in virus-induced inflammation and viral clearance will also be investigated. Two specific aims are proposed to address the long-term goal. Aim 1 investigates the cellular basis of Cmv5 locus dependent protection of secondary lymphoid organ (SLO) structure and NK cell accrual in spleen after MCMV infection. Cmv5 is predicted to protect stromal cells in the red and white pulp regions of the spleen. Aim1 therefore investigates the relationship between stromal cells and cytokines released by them, and their capability to support and/or regenerate SLO structure that may be further required to regulate leukocyte recruitment and retention. Aim 2 performs precision Cmv5 mapping and analysis of TREM expression, function and support of SLO structure after MCMV infection. A 16- Mb interval on mouse chr-17 is predicted to span the Cmv5 locus that regulates SLO structure, tissue necrosis and expansion of NK cells in spleen after virus infection. Inasmuch as the locus spans the Trem/Trem-like gene cluster that encodes myeloid-derived proteins needed to regulate inflammation, a further prediction is that one or more Trem / Trem-like proteins regulates SLO structure/function, NK cells expansion and enhancement of viral immunity.