Buying Time—The Immune System Determinants of the Incubation Period to Respiratory Viruses

Hermesh, Tamar; Moltedo, Bruno; López, Carolina B.; Moran, Thomas M.

Relationship between the incubation period of influenza virus and the immune response. For the first two days after influenza virus infection, the immune response is inactive ("stealth phase") due to viral antagonism and no symptoms are observed. The incubation period ends as symptoms abruptly appear about two days after infection when the innate immune response becomes active. The secretion of pro-inflammatory cytokines and chemokines is followed by a robust infiltration of leukocytes to the site of infection and DCs migration from the respiratory tract to the lung draining lymph nodes. The migrating DCs then present viral antigens and activate influenza specific T cells. About six days after infection, virus specific effector T cells infiltrate the lung to resolve the infection.