IFNA1 and infection: In a mouse model of pandemic IAV infection in which a recombinant virus expressing the HA and NA from the 1918 pandemic H1N1 virus in the genetic background of A/Texas/36/91 (H1N1) was used [26], depletion of alveolar macrophages prior to sublethal infection resulted in uncontrolled virus replication and 100% mortality associated with significantly reduced IFN-α and IFN-γ production, indicating that resident alveolar macrophages were functioning to promote viral clearance and thereby limited tissue injury.