The importance of CD8+ T cells in the immune response is well documented.  However, molecular mechanisms required to produce functionally intact antigen-specific CD8+ T cells are not well understood. CD27 is a lymphocyte restricted surface glycoprotein in the TNF receptor family, which is known to be important in the development and activation of CD8+ T-cells. We are examining the role of CD27 signaling in primary and secondary immune responses to Influenza Type A virus infection as well as it's role in CD8+ T-cell memory. We are also investigating the underlying mechanism by which CD27 influences CD8+ T-cell responses and the molecular targets of CD27 signaling.