Emerging role of dendritic cells in respiratory viral infection.

Respiratory viral infections are a major health problem, especially in the immunocompromised, young, and elderly. In order for the host to effectively clear viral infections, a productive adaptive immune response must be developed. Crucial to the initiation of the adaptive response is the dendritic cell, which induces the proliferation and activation of T cells early in an antiviral response. This review examines the role of lung dendritic cells in the immune response to respiratory viruses. The phenotypic and functional differences between conventional and plasmacytoid dendritic cells are discussed, as are the mechanisms behind homeostatic recruitment of these cells in the normal lung. Focusing on respiratory syncytial virus and influenza, the role of the two dendritic cell subsets during an antiviral response is explored. Through evolution, viruses have developed several mechanisms to interfere with the normal function of dendritic cells and prevent appropriate induction of an adaptive immune response, which are also discussed. Finally, we identify potential targets for future therapeutic strategies to ameliorate disease caused by respiratory virus infection.