T cell responses during influenza infection: getting and keeping control.

The 2009 influenza pandemic highlighted the threat that type A influenza poses to human health. Thus, there is an urgency to understand the pathobiology of influenza infection and the contribution of the host immune response to virus elimination and the development of lung injury. This review focuses on the T cell arm of the adaptive host immune response to influenza. We assess recent developments in the understanding of how primary influenza virus-specific T cell responses are induced by antigen-presenting cells, the interaction of activated effector T cells with antigen-bearing cells in the infected lungs. Also examined is the contribution of influenza-specific effector T cells to the development and control of lung injury and inflammation during infection.