Formation and function of tissue-resident memory T cells during viral infection

Memory T cells are an important component of the adaptive immune response. Tissue-resident memory T cells (T-RM) are a recently described subset of memory T cells that reside in peripheral tissues and are maintained independently of circulating subsets of memory T cells. Importantly, T-RM are frequently found in barrier tissues that commonly serve as entry portals for pathogens such as viruses. Mounting evidence shows that T-RM are superior to their circulating counterparts in conferring protective immunity against a wide range of viruses. In this review, we will discuss the role of T-RM in controlling viral infection with a focus on CD8+ T-RM, the factors that regulate differentiation and a potential role for T-RM in future vaccine development.