Surfactant protein-A--deficient mice display an exaggerated early inflammatory response to a beta-resistant strain of influenza A virus

Am J Respir Cell Mol Biol. 2002 Mar;26(3):277-82. doi: 10.1165/ajrcmb.26.3.4584.


Surfactant protein (SP)-A is a member of the collectin family of proteins. In vitro, SP-A binds influenza A virus (IAV), neutralizes infectivity, and enhances uptake by macrophages. SP-D also binds and neutralizes certain strains of IAV. To determine if SP-A has a role in protecting the intact animal against IAV infection, we inoculated gene-targeted SP-A-deficient mice (-/-) and littermate controls (+/+) with either saline or increasing doses of an IAV strain that binds SP-A but not SP-D. IAV was more virulent in SP-A-/- compared with +/+ mice, with a significantly lower mean lethal dose (LD(50)) and significantly greater weight loss during infection. SP-A-/- mice also had increased airway epithelial injury and more alveolar cellular infiltrates than +/+ mice. On Day 2, SP-A-/- mice had more neutrophils and higher MIP-2 levels in the lung than +/+ mice. We conclude the altered host response and increased susceptibility to X-79Delta167 infection in SP-A-/- mice reflects a protective role for SP-A in regulating the host response to IAV. Because the recovery of virus from lung homogenates on Days 2 and 6 after inoculation was comparable in -/- and +/+ mice, we speculate SP-A reduces IAV virulence independently of direct viral neutralization.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Immunity, Innate
  • Inflammation / immunology
  • Inflammation / virology
  • Influenza A virus / immunology
  • Influenza A virus / metabolism
  • Influenza A virus / pathogenicity*
  • Mice
  • Mice, Knockout
  • Orthomyxoviridae Infections / immunology*
  • Orthomyxoviridae Infections / virology
  • Proteolipids / immunology
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Proteins
  • Pulmonary Surfactants / deficiency*
  • Pulmonary Surfactants / immunology
  • Virulence


  • Proteolipids
  • Pulmonary Surfactant-Associated Protein A
  • Pulmonary Surfactant-Associated Proteins
  • Pulmonary Surfactants