Immunity to respiratory viruses

The respiratory tract is characterized by an extensive surface area that is in direct contact with the environment, posing a significant problem for effective immune surveillance. Yet most respiratory pathogens are quickly recognized and controlled by a coordinated response involving the innate and adaptive arms of the immune system. The investigation of pulmonary immunity to respiratory viruses during a primary infection has demonstrated that multiple innate and adaptive immune mechanisms are necessary for efficient antiviral responses, and the inhibition of any single mechanism can have disastrous consequences for the host. Furthermore, the investigation of recall responses in the lung has shown that protection from a secondary challenge infection is a complex and elegant process that occurs in distinct stages. In this review, we discuss recent advances that describe the roles of individual components during primary and secondary responses to respiratory virus infections and how these discoveries have added to our understanding of antiviral immunity in the lung.