Respiratory infections from influenza A virus (IAV) cause substantial morbidity and mortality in children relative to adults. T cells play a critical role in the host response to IAV by supporting the innate and humoral responses, mediating cytotoxic activity, and promoting recovery. There are age-dependent differences in the number, subsets, and localization of T cells, which impact the host response to pathogens. In this article, we first review how T cells recognize IAV and examine differences in the resting T-cell populations between juveniles and adults. Next, we describe how the juvenile CD4⁺, CD8⁺, and regulatory T-cell responses compare with those in adults and discuss the potential physiologic and clinical consequences of the differences. Finally, we explore the roles of two unconventional T-cell types in the juvenile response to influenza, natural-killer T cells and γδ T cells. A clear understanding of age-dependent differences in the T-cell response is essential to developing therapies to prevent or reverse the deleterious effects of IAV in children.

与成人相比，甲型流感病毒 (IAV) 引起的呼吸道感染在儿童中引起大量发病率和死亡率。T 细胞通过支持先天和体液反应、介导细胞毒活性和促进恢复，在宿主对 IAV 的反应中发挥关键作用。T 细胞的数量、亚群和定位存在年龄依赖性差异，这会影响宿主对病原体的反应。在本文中，我们首先回顾 T 细胞如何识别 IAV 并检查青少年和成人之间静息 T 细胞群的差异。接下来，我们描述一下少年CD4 ⁺、CD8 ⁺和调节性 T 细胞反应与成人的反应进行比较，并讨论差异的潜在生理和临床后果。最后，我们探讨了两种非常规 T 细胞类型在青少年对流感的反应中的作用，即自然杀伤 T 细胞和 γδ T 细胞。清楚地了解 T 细胞反应的年龄依赖性差异对于开发预防或逆转 IAV 对儿童的有害影响的疗法至关重要。