The Concept of Immunofocusing Illustrated by Influenza Virus Infection

Influenza virus infection is an often-cited example of viral infection associated with immunosuppression. However, immune responses to the virus are complex and more accurately reflect an immunofocusing of host defensive capabilities: non-virus-specific responses are depressed or actively suppressed, while virus-specific systemic, local, and recruited responses develop. The result is commonly a resolution of infection without significant residual disease and with emergence of homotypic immunity. The overall combination of depressed alternate responses and enhanced antiviral immune responses might be assumed to have net defensive value for the host challenged by influenza virus.