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Abstract：
The antigen presentation molecule MHC class I related protein-1 (MR1) is best characterized by its ability to present bacterially derived metabolites of vitamin B2 biosynthesis to mucosal-associated invariant T-cells (MAIT cells).
Through in vitro human cytomegalovirus (HCMV) infection in the presence of MR1 ligand we investigate the modulation of MR1 expression. Using coimmunoprecipitation, mass spectrometry, expression by recombinant adenovirus and HCMV deletion mutants we investigate HCMV gpUS9 and its family members as potential regulators of MR1 expression. The functional consequences of MR1 modulation by HCMV infection are explored in coculture activation assays with either Jurkat cells engineered to express the MAIT cell TCR or primary MAIT cells. MR1 dependence in these activation assays is established by addition of MR1 neutralizing antibody and CRISPR/Cas-9 mediated MR1 knockout.
Here we demonstrate that HCMV infection efficiently suppresses MR1 surface expression and reduces total MR1 protein levels. Expression of the viral glycoprotein gpUS9 in isolation could reduce both cell surface and total MR1 levels, with analysis of a specific US9 HCMV deletion mutant suggesting that the virus can target MR1 using multiple mechanisms. Functional assays with primary MAIT cells demonstrated the ability of HCMV infection to inhibit bacterially driven, MR1-dependent activation using both neutralizing antibodies and engineered MR1 knockout cells.
This study identifies a strategy encoded by HCMV to disrupt the MR1:MAIT cell axis. This immune axis is less well characterized in the context of viral infection. HCMV encodes hundreds of proteins, some of which regulate the expression of antigen presentation molecules. However the ability of this virus to regulate the MR1:MAIT TCR axis has not been studied in detail.
Through in vitro human cytomegalovirus (HCMV) infection in the presence of MR1 ligand we investigate the modulation of MR1 expression. Using coimmunoprecipitation, mass spectrometry, expression by recombinant adenovirus and HCMV deletion mutants we investigate HCMV gpUS9 and its family members as potential regulators of MR1 expression. The functional consequences of MR1 modulation by HCMV infection are explored in coculture activation assays with either Jurkat cells engineered to express the MAIT cell TCR or primary MAIT cells. MR1 dependence in these activation assays is established by addition of MR1 neutralizing antibody and CRISPR/Cas-9 mediated MR1 knockout.
Here we demonstrate that HCMV infection efficiently suppresses MR1 surface expression and reduces total MR1 protein levels. Expression of the viral glycoprotein gpUS9 in isolation could reduce both cell surface and total MR1 levels, with analysis of a specific US9 HCMV deletion mutant suggesting that the virus can target MR1 using multiple mechanisms. Functional assays with primary MAIT cells demonstrated the ability of HCMV infection to inhibit bacterially driven, MR1-dependent activation using both neutralizing antibodies and engineered MR1 knockout cells.
This study identifies a strategy encoded by HCMV to disrupt the MR1:MAIT cell axis. This immune axis is less well characterized in the context of viral infection. HCMV encodes hundreds of proteins, some of which regulate the expression of antigen presentation molecules. However the ability of this virus to regulate the MR1:MAIT TCR axis has not been studied in detail.
摘要：
未经证实:抗原呈递分子MHCI类相关蛋白-1(MR1)的最佳特征在于其将维生素B2生物合成的细菌衍生代谢物呈递至粘膜相关的不变T细胞(MAIT细胞)的能力。
UNASSIGNED：通过在MR1配体存在下的体外人巨细胞病毒（HCMV）感染，我们研究了MR1表达的调节。使用免疫共沉淀，质谱,通过重组腺病毒和HCMV缺失突变体的表达，我们研究了HCMVgpUS9及其家族成员作为MR1表达的潜在调节因子。通过HCMV感染的MR1调节的功能后果在与Jurkat细胞工程化以表达MAIT细胞TCR或原代MAIT细胞的共培养激活测定中进行了探索。通过添加MR1中和抗体和CRISPR/Cas-9介导的MR1敲除来建立这些活化测定中的MR1依赖性。
UNASSIGNED：在这里，我们证明HCMV感染有效地抑制了MR1表面表达并降低了总MR1蛋白水平。分离的病毒糖蛋白gpUS9的表达可以降低细胞表面和总MR1水平，对特定US9HCMV缺失突变体的分析表明该病毒可以使用多种机制靶向MR1。使用原代MAIT细胞的功能测定证明了HCMV感染抑制细菌驱动的能力，使用中和抗体和工程化MR1敲除细胞的MR1依赖性活化。
未授权：本研究确定了HCMV编码的破坏MR1:MAIT细胞轴的策略。这种免疫轴在病毒感染的情况下没有很好地表征。HCMV编码数百种蛋白质，其中一些调节抗原呈递分子的表达。然而,尚未详细研究该病毒调节MR1:MAITTCR轴的能力。
UNASSIGNED：通过在MR1配体存在下的体外人巨细胞病毒（HCMV）感染，我们研究了MR1表达的调节。
UNASSIGNED：在这里，我们证明HCMV感染有效地抑制了MR1表面表达并降低了总MR1蛋白水平。
未授权：本研究确定了HCMV编码的破坏MR1:MAIT细胞轴的策略。
