AbstractsBiology & Animal Science

The study of T cell immunity at barrier surfaces has largely focused on T cells bearing the ???? T cell receptor. However, T cells that express the ???? T cell receptor are disproportionately represented in peripheral tissues of mice and humans, suggesting they too may play an important role responding to external stimuli. Here we report that in a murine model of cutaneous infection with Vaccinia Virus, dermal ???? T cell numbers increased ten-fold in the infected ear and resulted in a novel ???? T cell population not found in na????ve skin. Circulating ???? T cells were specifically recruited to the site of inflammation and differentially contributed to dermal populations based on their CD27 expression. Recruited ???? T cells, the majority of which were CD27+, were Granzyme B+ and made up about half of the dermal population at the peak of the response. In contrast, recruited and resident ???? T cell populations that made IL-17 were CD27-. Using a double chimera model that can discriminate between the resident dermal and recruited ???? T cell populations, we demonstrated their divergent functions and contributions to early stages of tissue inflammation. Specifically, the loss of the perinatal thymus-derived resident dermal population resulted in decreased cellularity and collateral damage in the tissue during viral infection. These findings have important implications for our understanding of immune coordination at barrier surfaces and the contribution of innate-like lymphocytes on the front lines of immune defense.