Immune response

When the influenza virus infects the cells of the respiratory tract, both innate and adaptive immune responses are stimulated. The innate immune response develops very quickly and controls virus replication during the early stages of infection. The cytokines produced during this early phase in turn facilitate the activation of antigen-specific adaptive immune mechanisms. Adaptive immune responses develop immunological memory that provides a more rapid response upon re-exposure to the virus through the production of virus-specific antibodies and cytotoxic T lymphocytes (CTLs).