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Updated: Jul 15, 2026
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Selective Harvesting of Marginating-pulmonary Leukocytes
Published on: March 11, 2016
Natural killer cells are present in the normal human lung but are functionally impotent
The Journal of Clinical Investigation
|September 1, 1984
Summary
Natural killer (NK) cells in the lungs show low activity due to local suppression, but can be activated by Interleukin-2 (IL-2). This finding is crucial for understanding lung immunity and disease.
Area of Science:
- Immunology
- Pulmonology
- Cellular Biology
Background:
- Natural killer (NK) cells are crucial for lung defense against pathogens and tumors.
- Previous assumptions suggested high NK cell activity in the lung for immune surveillance.
Purpose of the Study:
- To investigate the functional activity of NK cells in the normal human lung.
- To identify factors within the lung microenvironment that may regulate NK cell function.
Main Methods:
- Compared NK cell activity of lung-derived lymphocytes versus blood lymphocytes using various NK-sensitive target cells.
- Assessed the impact of alveolar macrophages and epithelial lining fluid on NK cell cytotoxicity.
- Investigated the modulation of NK cell activity by incubation, Interleukin-2 (IL-2), and gamma interferon.
- Examined NK cell activity in lung lymphocytes from patients with active sarcoidosis.
Main Results:
- Normal lung lymphocytes exhibited significantly lower NK cell activity compared to blood lymphocytes.
- Despite similar cell surface markers, lung NK cells showed impaired target cell lysis.
- Alveolar macrophages and epithelial lining fluid suppressed blood NK cell activity.
- Lung NK cell activity was enhanced after 24-hour incubation and further augmented by IL-2.
- Lung lymphocytes from sarcoidosis patients displayed significant NK cell activity.
Conclusions:
- NK cells in the normal lung are functionally suppressed by local inhibitory factors.
- Lung NK cells possess the potential for activity, which can be restored and enhanced.
- IL-2 plays a key role in activating lung NK cell function, relevant to inflammatory lung diseases.
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