原理:次优疫苗免疫原性和抗原错配,再加上吸收不足,意味着流感仍然是一种主要的全球性疾病。T细胞识别来自保守病毒蛋白的肽可以增强疫苗诱导的交叉株保护。目的:研究动力学,表型,和流感病毒特异性CD8+驻留记忆T(Trm)细胞在下气道中的功能,并推断与其体内感染反应相关的分子途径。方法:健康志愿者,年龄18-55岁,鼻内接种流感A/California/4/09(H1N1)。血,上呼吸道,和(在一个亚组中)在整个感染过程中获得下气道样本。通过使用自我报告的日记来评估症状,通过定量PCR评估鼻腔病毒载量。使用三色荧光斑点测定法分析T细胞反应,用MHCI肽四聚体流式细胞术,和RNA测序,通过使用支气管内活检标本的免疫组织化学结果来确认候选标志物。测量和主要结果:挑战后,57%的参与者被感染。血液中预先存在的流感特异性CD8+T细胞与病毒载量降低密切相关。在第三天达到顶峰。BAL液中的流感特异性CD8+T细胞高度富集并主要表达Trm标志物CD69和CD103。通过使用RNA测序在BAL液中和血液中的感染前CD8T细胞之间的比较显示3,928个差异表达基因,包括所有主要的Trm细胞标记。然而,BAL液CD8+T细胞的基因集富集分析主要显示先天细胞相关途径,在感染期间,包括先天性趋化因子(Cxcl1,Cxcl10和Cxcl16)的上调,这些趋化因子也由支气管组织中的CD8细胞表达。结论:人肺中的CD8Trm细胞显示出先天样基因和蛋白质表达,表明先天和适应性免疫之间的分裂模糊。在www上注册的临床研究。clinicaltrials.gov(NCT02755948)。
Rationale: Suboptimal vaccine immunogenicity and antigenic mismatch, compounded by poor uptake, means that influenza remains a major global disease. T cells recognizing peptides derived from conserved viral proteins could enhance vaccine-induced cross-strain protection. Objectives: To investigate the kinetics, phenotypes, and function of influenza virus-specific CD8+ resident memory T (Trm) cells in the lower airway and infer the molecular pathways associated with their response to infection in vivo. Methods: Healthy volunteers, aged 18-55, were inoculated intranasally with influenza A/California/4/09(H1N1). Blood, upper airway, and (in a subgroup) lower airway samples were obtained throughout infection. Symptoms were assessed by using self-reported diaries, and the nasal viral load was assessed by using quantitative PCR. T-cell responses were analyzed by using a three-color FluoroSpot assay, flow cytometry with MHC I-peptide tetramers, and RNA sequencing, with candidate markers being confirmed by using the immunohistochemistry results for endobronchial biopsy specimens. Measurements and Main Results: After challenge, 57% of participants became infected. Preexisting influenza-specific CD8+ T cells in blood correlated strongly with a reduced viral load, which peaked at Day 3. Influenza-specific CD8+ T cells in BAL fluid were highly enriched and predominantly expressed the Trm markers CD69 and CD103. Comparison between preinfection CD8+ T cells in BAL fluid and blood by using RNA sequencing revealed 3,928 differentially expressed genes, including all major Trm-cell markers. However, gene set enrichment analysis of BAL-fluid CD8+ T cells showed primarily innate cell-related pathways and, during infection, included upregulation of innate chemokines (Cxcl1, Cxcl10, and Cxcl16) that were also expressed by CD8+ cells in bronchial tissues. Conclusions: CD8+ Trm cells in the human lung display innate-like gene and protein expression that demonstrates blurred divisions between innate and adaptive immunity. Clinical study registered with www.clinicaltrials.gov (NCT02755948).