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[Alveolar macrophage subpopulations and circulating monocytes. Immunophenotypic study in healthy non-smokers]
1Università di Torino, Clinica delle Malattie dell'Apparato Respiratorio, Facoltà di Medicina, Ospedale S. Luigi Gonzaga, Orbassano.
Insights
Peripheral blood monocytes and alveolar macrophages exhibit distinct marker expressions. Alveolar macrophages (MA) differentiate into three phenotypes (MAC 387+/CD14-, MAC 387+/CD14+, MAC 387-/CD14+), indicating diverse functional roles.
Area of Science:
- Immunology
- Cell Biology
Context:
- Peripheral blood monocytes and bronchoalveolar lavage (BAL) fluid macrophages were analyzed in 10 non-smoker subjects.
- Two monoclonal antibodies, MAC 387 and CD14, were used to identify cell surface markers.
Purpose:
- To investigate the differential expression of MAC 387 and CD14 markers on monocytes and alveolar macrophages.
- To categorize alveolar macrophages into distinct phenotypes based on marker expression.
Summary:
- Monocytes express both MAC 387 and CD14 markers simultaneously.
- Alveolar macrophages (MA) were classified into three phenotypes: MAC 387+/CD14-, MAC 387+/CD14+, and MAC 387-/CD14+.
- The MAC 387+/CD14+ phenotype was associated with adherent cells lacking anthracosis, potentially representing blood monocyte turnover.
Impact:
- This study reveals phenotypic heterogeneity within alveolar macrophages in non-smokers.
- Understanding these macrophage phenotypes provides insights into pulmonary immune surveillance and cellular dynamics.
- The findings contribute to the characterization of normal lung immune cell populations.
Abstract:
Peripheral blood monocytes of 10 non-smoker normal subjects and the macrophages of their bronchoalveolar lavage fluid (BAL) were investigated with two commercially available monoclonal antibodies (MAC 387, CD14). Surface membrane monocyte cells show simultaneously both markers. Instead alveolar macrophage (MA) can be divided in three different phenotype groups by the expression of the two markers (MAC 387+/CD14-, MAC 387+/CD14+, MAC 387-/CD14+). Particularly, MA with MAC 387+/CD14+ phenotype are adherent cells and morphologically lack anthracosis. Their alveolar presence in non-smokers can be due to normal turnover of monocytes from blood into alveoli. By contrast MA with MAC 387+/CD14- phenotype are non-adherent cells without anthracosis. At last MA with MAC 387-/CD14+ phenotype are non-adherent cells but different amounts of anthracosis in their cytoplasm can be observed.