Tissue resident memory T cells in respiratory infections

PURPOSE OF REVIEW: We review the latest evidence that respiratory tissue resident memory T (T RM ) cells are key to local and immediate adaptive immunity to bacterial and viral infections of the respiratory tract and the implication for the design of new or improved vaccines. RECENT FINDINGS: Recent research on respiratory T RM cells in mouse models have focused our view of T RM cells as frontline, antipathogen sentinels and provided new insights into the induction, function, regulation and maintenance of these cells at mucosal sites. Novel sampling techniques for recovery of immune cells from human nasal mucosa and lungs have enabled detailed studies on human respiratory T RM cells, which have led to significant advances in our understanding of the function and tissue adaptation of T RM in the human respiratory tract. SUMMARY: Emerging insights into the biology of T RM differentiation and persistence are directly informing the rational design of next-generation vaccines aimed at enhancing mucosal immunity, with nasal delivery consistently shown to elicit robust T RM responses in the lung, nose and other mucosal sites.