BACKGROUND Although γδ T cells comprise up to 10% of human peripheral blood T cells, questions remain regarding their role in disease states and T-cell receptor (TCR) clonal expansions. We dissected anti-viral functions of human γδ T cells towards influenza viruses and defined influenza-reactive γδ TCRs in the context of γδ-TCRs across the human lifespan. METHODS We performed 51Cr-killing assay and single-cell time-lapse live video microscopy to define mechanisms underlying γδ T-cell-mediated killing of influenza-infected targets. We assessed cytotoxic profiles of γδ T cells in influenza-infected patients and IFN-γ production towards influenza-infected lung epithelial cells. Using single-cell RT-PCR, we characterised paired TCRγδ clonotypes for influenza-reactive γδ T cells in comparison with TCRs from healthy neonates, adults, elderly donors and tissues. RESULTS We provide the first visual evidence of γδ T-cell-mediated killing of influenza-infected targets and show distinct features to those reported for CD8+ T cells. γδ T cells displayed poly-cytotoxic profiles in influenza-infected patients and produced IFN-γ towards influenza-infected cells. These IFN-γ-producing γδ T cells were skewed towards the γ9δ2 TCRs, particularly expressing the public GV9-TCRγ, capable of pairing with numerous TCR-δ chains, suggesting their significant role in γδ T-cell immunity. Neonatal γδ T cells displayed extensive non-overlapping TCRγδ repertoires, while adults had enriched γ9δ2-pairings with diverse CDR3γδ regions. Conversely, the elderly showed distinct γδ-pairings characterised by large clonal expansions, a profile also prominent in adult tissues. CONCLUSION Human TCRγδ repertoire is shaped by age, tissue compartmentalisation and the individual's history of infection, suggesting that these somewhat enigmatic γδ T cells indeed respond to antigen challenge.

中文翻译：

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人类 γδ T 细胞受体库受流感病毒、年龄和组织划分的影响。

背景尽管 γδ T 细胞占人类外周血 T 细胞的比例高达 10%，但关于它们在疾病状态和 T 细胞受体 (TCR) 克隆扩增中的作用仍然存在疑问。我们剖析了人类 γδ T 细胞对流感病毒的抗病毒功能，并在整个人类生命周期的 γδ-TCRs 的背景下定义了流感反应性 γδTCRs。方法 我们进行了 51Cr 杀伤试验和单细胞延时实时视频显微镜，以确定 γδ T 细胞介导的流感感染靶标杀伤机制。我们评估了流感感染患者中 γδ T 细胞的细胞毒性谱和流感感染肺上皮细胞产生的 IFN-γ。使用单细胞 RT-PCR，我们将流感反应性 γδ T 细胞的 TCRγδ 克隆型与来自健康新生儿、成人、老年捐赠者和组织。结果 我们提供了γδ T 细胞介导的流感感染靶点杀伤的第一个视觉证据，并显示出与报道的 CD8+ T 细胞不同的特征。γδ T 细胞在流感感染患者中表现出多细胞毒性特征，并对流感感染细胞产生 IFN-γ。这些产生 IFN-γ 的 γδ T 细胞偏向于 γ9δ2 TCR，特别是表达公共 GV9-TCRγ，能够与许多 TCR-δ 链配对，表明它们在 γδ T 细胞免疫中的重要作用。新生儿 γδ T 细胞显示出广泛的非重叠 TCRγδ 库，而成人则丰富了具有不同 CDR3γδ 区域的 γ9δ2 配对。相反，老年人表现出明显的 γδ 配对，其特征是大的克隆扩增，这一特征在成人组织中也很突出。