Cigarette smoking decreases bioactive interleukin-6 secretion by alveolar macrophages

D. M. Soliman, H. L. Twigg

Research output: Contribution to journalArticle

88 Scopus citations


Studies suggest smokers have decreased alveolar macrophage (AM) accessory cell (AC) function and a reduced incidence of immune-mediated lung diseases such as sarcoidosis. Impaired AM secretion of cytokines important in T-cell immune responses could explain this observation. We investigated production and secretion of interleukin-1 (IL-1) and interleukin-6 (IL-6) in smokers and nonsmokers. Lipopolysaccharide-induced AM IL-1 secretion in smokers was significantly reduced compared with nonsmoker AM. However, intracellular IL-1 in smoker AM was higher than in nonsmokers, suggesting that reduced IL-1 secretion was due to impaired release rather than reduced production. Smoker AM secreted significantly less bioactive IL-6 measured in a bioassay compared with nonsmoker AM. Intracellular IL-6 was virtually undetectable in both groups. In some smokers IL-6 production determined by immunoprecipitation was reduced. However, as a group antigenic IL-6 secretion determined by enzyme- linked immunoabsorbent assay was similar in smokers and nonsmokers, suggesting that smoker AM may cosecrete an inhibitor of IL-6 bioactivity. Indeed, AM supernatants from smokers inhibited B9 proliferation in response to maximal recombinant IL-6 stimulation, whereas supernatants from nonsmokers did not. We conclude that AM from smokers secrete less cytokines important in T-cell proliferation than AM from nonsmokers and suggest that for IL-6 this impairment is related to both decreased production of antigenic protein as well as cosecretion of an IL-6 inhibitor.

Original languageEnglish (US)
Pages (from-to)L471-L478
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number4 7-4
StatePublished - Jan 1 1992


  • accessory cells
  • cytokines
  • interleukin-1
  • interleukin-6 inhibitor

ASJC Scopus subject areas

  • Cell Biology
  • Physiology
  • Pulmonary and Respiratory Medicine

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