Human circulating and tissue-resident memory CD8+ T cells

Our current knowledge of human memory CD8(+) T cells is derived largely from studies of the intravascular space. However, emerging data are starting to challenge some of the dogmas based on this work, suggesting that a conceptual revision may be necessary. In this review, we provide a brief history of the field and summarize the biology of circulating and tissue-resident memory CD8(+) T cells, which are ultimately responsible for effective immune surveillance. We also incorporate recent findings into a biologically integrated model of human memory CD8(+) T cell differentiation. Finally, we address how future innovative human studies could improve our understanding of anatomically localized CD8(+) T cells to inform the development of more effective immunotherapies and vaccines, the need for which has been emphasized by the global struggle to contain severe acute respiratory syndrome coronavirus 2. Buggert and colleagues provide a broad picture in this review of circulating and tissue-resident memory CD8(+) T cells, which are ultimately responsible for effective immune surveillance.