Influenza A Virus Infects Macrophages and Stimulates Release of Tumor Necrosis Factor-Alpha

Pathobiology. 1991;59(4):227-31. doi: 10.1159/000163651.


The clinical picture of influenza A virus infections indicates that release of tumor necrosis factor-alpha (TNF-alpha) may be involved. In the present study we exposed the murine macrophage line PU5-1.8 to influenza A virus and observed a productive infection which was followed by subsequent cell death. Infection of macrophages was accompanied by TNF-alpha mRNA accumulation and TNF-alpha release. TNF-alpha production could only be induced by live virus whereas interferon release was also stimulated by inactivated virus. When virus-infected macrophages were exposed to low amounts of lipopolysaccharide (LPS; 1-10 ng/ml) TNF-alpha production was strongly potentiated. These data show that low LPS concentrations could readily trigger a high TNF-alpha release from influenza-A-virus-infected macrophages which could, at least partially, explain the serious complications of combined influenza A virus and bacterial infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Influenza A virus / pathogenicity*
  • Kinetics
  • Lipopolysaccharides / pharmacology
  • Macrophages / metabolism
  • Macrophages / microbiology*
  • Orthomyxoviridae Infections / physiopathology
  • RNA, Messenger / metabolism
  • Tumor Necrosis Factor-alpha / metabolism*


  • Lipopolysaccharides
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha