The pathogen recognition theory dictates that, upon viral infection, the innate immune system first detects microbial products and then responds by providing instructions to adaptive CD8 T cells. Here, we show in mice that tissue resident memory CD8 T cells (T(RM) cells), non-recirculating cells located at common sites of infection, can achieve near-sterilizing immunity against viral infections by reversing this flow of information. Upon antigen resensitization within the mouse female reproductive mucosae, CD8(+) T(RM) cells secrete cytokines that trigger rapid adaptive and innate immune responses, including local humoral responses, maturation of local dendritic cells, and activation of natural killer cells. This provided near-sterilizing immunity against an antigenically unrelated viral infection. Thus, CD8(+) T(RM) cells rapidly trigger an antiviral state by amplifying receptor-derived signals from previously encountered pathogens.
Schenkel, J. M., Fraser, K. A., Beura, L. K., Pauken, K. E., Vezys, V., & Masopust, D. (2014). Resident memory CD8 t cells trigger protective innate and adaptive immune responses. Science, 346(6205), 98–101. https://doi.org/10.1126/science.1254536