Murine CMV Infection Induces the Continuous Production of Mucosal Resident T Cells

Cytomegalovirus (CMV) is a herpesvirus that persists for life and maintains extremely large numbers of T cells with select specificities in circulation. However, it is unknown how viral persistence impacts T cell populations in mucosal sites. We found that many murine (M) CMV-specific CD8s in mucosal tissues became resident memory T cells (T-RM). These cells adopted an intraepithelial localization in the salivary gland that correlated with, but did not depend on, expression of the integrin CD103. MCMV-specific T-RM cells formed early after infection, and spleen-localized cells had reduced capacities to become T-RM at late times. Surprisingly, however, small numbers of new T-RM cells were formed from the circulating pool throughout infection, favoring populations maintained at high levels in the blood and shifting the immunodominance within the T-RM populations over time. These data show that mucosal T-RM populations can be dynamically maintained by a persistent infection.