The importance of SP-D in protecting against IAV infection in vivo has been demonstrated by the use of SP-D knockout mice (SP-D -/-) that, upon infection by IAV, show increased lung virus titers and weight loss as compared to wildtype mice (42, 43); pulmonary instillation or over-expression of SP-D can correct these effects (44, 45). The gene discussed is SFTPD; the disease is infection.