Bronchoalveolar macrophage CD14 expression: Shift between membrane- associated and soluble pools

Jeffrey D. Hasday, Wendy Dubin, Steven Mongovin, Simeon E. Goldblum, Peggy Swoveland, Didier J. Leturcq, Ann M. Moriarty, Eugene R. Bleecker, Thomas R. Martin

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The bacterial endotoxin [lipopolysaccharide (LPS)]-binding protein CD14 modulates the host response to LPS, but membrane-associated and soluble forms of the molecule exert different biological effects. CD14 anchored to the mononuclear phagocyte membrane (mCD14) enhances response to LPS. Soluble CD14 (sCD14) may block LPS stimulation of CD14-bearing cells while supporting LPS presentation to non-CD14-bearing cells. We analyzed cell mCD4 and sCD14 expression in simultaneously collected human bronchoalveolar macrophages (BAM) and peripheral blood monocytes (PBM). Expression of mCD14 in freshly isolated BAM was only 9% as high as in PBM. Levels of sCD14 in 48 h in BAM culture supernatants were 19% as high as in PBM cultures. Interleukin (IL)-6 increased CD14 expression in both BAM and PBM but exerted different effects on CD14 distribution in these cell types. IL-6 increased only sCD14 release (2.5-fold) in BAM while increasing only mCD14 expression (2.5-fold) in PBM. IL-4 reduced both mCD14 (>40%) and sCD14 (>60% expression in both cell types. We speculate that the balance between sCD14 and mCD14 expression influences the response to aspirated or inhaled LPS in the bronchoalveolar compartment. Cytokine expression and monocyte recruitment may influence this process by modulating CD14 expression.

Original languageEnglish (US)
Pages (from-to)L925-L933
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume272
Issue number5 16-5
DOIs
StatePublished - May 1997
Externally publishedYes

Keywords

  • Bronchoalveolar lavage
  • Interleukin-4
  • Interleukin-6
  • Monocyte
  • Pulmonary

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

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