Age-dependent Differences in T Cell Responses to Influenza A Virus.Am J Respir Cell Mol Biol. 2020 Jul 01 [Online ahead of print]AJ
Respiratory infections from influenza A virus cause substantial morbidity and mortality in children relative to adults. T cells play a critical role in the host response to influenza A virus 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 influenza A virus 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 to 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 gamma-delta 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 influenza A virus in children.