Recent studies have shown that recall responses to respiratory virus infections of the lung involve the sequential mobilization of distinct pools of memory CD8+ T cells. The initial response is mediated by effector/memory cells resident in the lung airways. This is followed by recruitment of circulating non-dividing effector/memory cells (days 2-7 post infection) and the recruitment of proliferating effector cells from the lymph nodes days 5-11 post-infection).
To better understand the memory recall response we are investigating the regulation and mobilization of these memory T cell pools. First, we are analyzing the factors (chemokines, cytokines, etc) involved in the long-term maintenance of memory T cells in the lung airways. Second we are identifying the subpopulations of memory T cells that are recruited to the lungs during the early phase of the recall response. Third, we are determining the relative contributions of these different subsets of memory T cells to the efficacy of the recall response. And fourth we are investigating which subpopulations of memory cells are elicited by different vaccine strategies (systemic and mucosal) and how this impacts the quality of the recall response. These studies will generate insights into the development of vaccines that promote cellular immunity in the lung.