Kaabinejadian Saghar, McMurtrey Curtis P, Kim Sojung, Jain Rinki, Bardet Wilfried, Schafer Fredda B, Davenport Jason L, Martin Aaron D, Diamond Michael S, Weidanz Jon A, Hansen Ted H, Hildebrand William H
Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104;
Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110;
J Immunol. 2016 May 15;196(10):4263-73. doi: 10.4049/jimmunol.1501821. Epub 2016 Apr 20.
Class I HLA molecules mark infected cells for immune targeting by presenting pathogen-encoded peptides on the cell surface. Characterization of viral peptides unique to infected cells is important for understanding CD8(+) T cell responses and for the development of T cell-based immunotherapies. Having previously reported a series of West Nile virus (WNV) epitopes that are naturally presented by HLA-A*02:01, in this study we generated TCR mimic (TCRm) mAbs to three of these peptide/HLA complexes-the immunodominant SVG9 (E protein), the subdominant SLF9 (NS4B protein), and the immunorecessive YTM9 (NS3 protein)-and used these TCRm mAbs to stain WNV-infected cell lines and primary APCs. TCRm staining of WNV-infected cells demonstrated that the immunorecessive YTM9 appeared several hours earlier and at 5- to 10-fold greater density than the more immunogenic SLF9 and SVG9 ligands, respectively. Moreover, staining following inhibition of the TAP demonstrated that all three viral ligands were presented in a TAP-dependent manner despite originating from different cellular compartments. To our knowledge, this study represents the first use of TCRm mAbs to define the kinetics and magnitude of HLA presentation for a series of epitopes encoded by one virus, and the results depict a pattern whereby individual epitopes differ considerably in abundance and availability. The observations that immunodominant ligands can be found at lower levels and at later time points after infection suggest that a reevaluation of the factors that combine to shape T cell reactivity may be warranted.
I类HLA分子通过在细胞表面呈递病原体编码的肽来标记受感染的细胞，使其成为免疫靶向的目标。鉴定受感染细胞特有的病毒肽对于理解CD8(+) T细胞反应以及基于T细胞的免疫疗法的开发至关重要。此前我们报道了一系列由HLA-A*02:01自然呈递的西尼罗河病毒（WNV）表位，在本研究中，我们针对其中三种肽/HLA复合物——免疫显性的SVG9（E蛋白）、次显性的SLF9（NS4B蛋白）和免疫隐性的YTM9（NS3蛋白）——产生了TCR模拟（TCRm）单克隆抗体，并使用这些TCRm单克隆抗体对WNV感染的细胞系和原代抗原呈递细胞（APC）进行染色。对WNV感染细胞的TCRm染色表明，免疫隐性的YTM9比免疫原性更强的SLF9和SVG9配体分别提前数小时出现，且密度高5至10倍。此外，在抑制抗原加工相关转运体（TAP）后进行的染色表明，尽管这三种病毒配体来自不同的细胞区室，但它们都是以TAP依赖的方式呈递的。据我们所知，本研究首次使用TCRm单克隆抗体来确定一种病毒编码的一系列表位的HLA呈递动力学和程度，结果描绘了一种模式，即各个表位在丰度和可及性上有很大差异。免疫显性配体在感染后较低水平和较晚时间点被发现的观察结果表明，可能有必要重新评估影响T细胞反应性的综合因素。
