Host defense against virus infection can be divided into primary defenses and immune defenses . The adaptive response also has memory in that subsequent infections by the same virus are met with a more rapid response of higher intensity. The innate immune response engages the initial infection but the adaptive response is essential in eradication of infected cells and clearance of the infection . Antibodies bind to the virus in circulation and at mucosal surfaces, decreasing the amount of virus available to infected cells and tissues.
T cells recognize and kill infected cells.
Both are essential in antiviral defense and act in concert but their respective roles varies with host species and infecting virus. The inflammatory response Is a complex sequence of events, involving synergy between innate and adaptive immune response, that are induced by cell and tissue damage caused by cytopathic virus infection. Non-cytophathic virus induce a very weak inflammatory response. The mechanisms by which the inflammatory response is induced are not clearly understood. Neutrophils, which are found in blood but not in normal tissues are the earliest phagocytic cells to be recruited to the infection site.