Lymphatic vessel transit seeds cytotoxic resident memory T cells in skin draining lymph nodes
Taylor A. Heim, Austin C. Schultz, Ines Delclaux, Vanessa Cristaldi, Madeline J. Churchill, Katherine S. Ventre, Amanda W. Lund
Abstract
Lymphatic transport shapes the homeostatic immune repertoire of lymph nodes (LNs). LN-resident memory T cells (T RMs ) play an important role in site-specific immune memory, yet how LN T RMs form de novo after viral infection remains unclear. Here, we tracked the anatomical distribution of antiviral CD8 + T cells as they seeded skin and LN T RMs using a model of vaccinia virus–induced skin infection. LN T RMs localized to the draining LNs (dLNs) of infected skin, and their formation depended on the lymphatic egress of effector CD8 + T cells from the skin, already poised for residence. Effector CD8 + T cell transit through skin was required to populate LN T RMs in dLNs, a process reinforced by antigen encounter in skin. Furthermore, LN T RMs were protective against viral rechallenge in the absence of circulating memory T cells. These data suggest that a subset of tissue-infiltrating CD8 + T cells egress from tissues during viral clearance and establish a layer of regional protection in the dLN basin.