Imaging of T Cell Trafficking in a Mouse Model of Influenza Tracheitis This project is focused on identifying the specificities of T cell responses to influenza in both animal models and in humans. Although humans possess immune responses that cross-react against different subtypes of influenza (so-called heterosubtypic immunity), there is little evidence of its specificity, and the reasons why it may or may not be protective are unclear. Our lab has shown that optimal CD8 T cell mediated heterosubtypic immunity is provided when T cells are retained in the lung tissue and airways via their interaction with collagen via the VLA-1 collagen receptor. One hypothesis is that heterosubtypic immunity to influenza fails in humans because of insufficient memory in the lung tissue. We propose to develop the means to test this hypothesis.