BACKGROUNDRespiratory syncytial virus (RSV) is an important cause of acute pulmonary disease and one of the last remaining major infections of childhood for which there is no vaccine. CD4+ T cells play a key role in antiviral immunity, but they have been little studied in the human lung.METHODSHealthy adult volunteers were inoculated i.n. with RSV A Memphis 37. CD4+ T cells in blood and the lower airway were analyzed by flow cytometry and immunohistochemistry. Bronchial soluble mediators were measured using quantitative PCR and MesoScale Discovery. Epitope mapping was performed by IFN-γ ELISpot screening, confirmed by in vitro MHC binding.RESULTSActivated CD4+ T cell frequencies in bronchoalveolar lavage correlated strongly with local C-X-C motif chemokine 10 levels. Thirty-nine epitopes were identified, predominantly toward the 3' end of the viral genome. Five novel MHC II tetramers were made using an immunodominant EFYQSTCSAVSKGYL (F-EFY) epitope restricted to HLA-DR4, -DR9, and -DR11 (combined allelic frequency: 15% in Europeans) and G-DDF restricted to HLA-DPA1*01:03/DPB1*02:01 and -DPA1*01:03/DPB1*04:01 (allelic frequency: 55%). Tetramer labeling revealed enrichment of resident memory CD4+ T (Trm) cells in the lower airway; these Trm cells displayed progressive differentiation, downregulation of costimulatory molecules, and elevated CXCR3 expression as infection evolved.CONCLUSIONSHuman infection challenge provides a unique opportunity to study the breadth of specificity and dynamics of RSV-specific T-cell responses in the target organ, allowing the precise investigation of Trm recognizing novel viral antigens over time. The new tools that we describe enable precise tracking of RSV-specific CD4+ cells, potentially accelerating the development of effective vaccines.TRIAL REGISTRATIONClinicalTrials.gov NCT02755948.FUNDINGMedical Research Council, Wellcome Trust, National Institute for Health Research.

中文翻译：

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实验性人类 RSV 感染期间表位特异性气道驻留 CD4+ T 细胞动态。


背景呼吸道合胞病毒（RSV）是急性肺部疾病的重要原因，也是目前尚无疫苗的儿童最后剩下的主要感染之一。 CD4+ T细胞在抗病毒免疫中发挥着关键作用，但在人肺中的研究很少。方法健康成年志愿者接种RSV A Memphis 37。通过流式细胞术和免疫组化分析血液和下呼吸道中的CD4+ T细胞。使用定量 PCR 和 MesoScale Discovery 测量支气管可溶性介质。通过 IFN-γ ELISpot 筛选进行表位作图，并通过体外 MHC 结合进行证实。结果支气管肺泡灌洗液中活化的 CD4+ T 细胞频率与局部 CXC 基序趋化因子 10 水平密切相关。鉴定出 39 个表位，主要位于病毒基因组的 3' 端。使用仅限于 HLA-DR4、-DR9 和 -DR11（组合等位基因频率：欧洲人中的 15%）的免疫显性 EFYQSTCSAVSKGYL (F-EFY) 表位和仅限于 HLA-DPA1*01 的 G-DDF 制备了五个新型 MHC II 四聚体:03/DPB1*02:01 和 -DPA1*01:03/DPB1*04:01（等位基因频率：55%）。四聚体标记显示下呼吸道中常驻记忆 CD4+ T (Trm) 细胞富集；随着感染的发展，这些 Trm 细胞表现出渐进分化、共刺激分子下调和 CXCR3 表达升高。结论人类感染挑战提供了一个独特的机会来研究靶器官中 RSV 特异性 T 细胞反应的特异性和动态范围，从而允许随着时间的推移，对 Trm 识别新病毒抗原的精确研究。我们描述的新工具能够精确追踪 RSV 特异性 CD4+ 细胞，有可能加速有效疫苗的开发。试验注册ClinicalTrials.gov NCT02755948.FUNDING医学研究委员会、Wellcome Trust、国家健康研究所。