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Modulation of natural killer cell function by human alveolar macrophages
The Journal of Allergy and Clinical Immunology
|October 1, 1986
Summary
Pulmonary alveolar macrophages (PAM) from smokers suppress natural killer (NK) cell activity. This suppression increases with higher ratios of PAM to lymphocytes, potentially impairing lung immunity.
Area of Science:
- Immunology
- Pulmonary Medicine
- Cell Biology
Background:
- Natural killer (NK) cell activity is crucial for defense against viral infections and cancer.
- Pulmonary alveolar macrophages (PAM) from non-smokers are known to suppress NK activity.
- Smoking is associated with increased numbers of PAM in the lungs.
Purpose of the Study:
- To investigate whether PAM derived from smokers modulate NK activity.
- To compare the NK-suppressive capacity of PAM from smokers and non-smokers.
Main Methods:
- Bronchoalveolar lavage cells (BLC) were collected from healthy smokers and non-smokers.
- BLC were co-cultured with peripheral blood lymphocytes (PBL) and K562 tumor target cells.
- NK activity was measured by the ability of PBL to lyse tumor targets at varying BLC:PBL ratios.
Main Results:
- Increasing numbers of BLC from both smokers and non-smokers progressively suppressed NK activity.
- Smoker and non-smoker BLC exhibited similar potency in inhibiting NK activity.
- Suppression was not reversed by indomethacin, catalase, or BLC culture supernatants and affected even activated NK cells.
Conclusions:
- PAM derived from smokers efficiently suppress lymphocyte NK activity.
- The degree of NK suppression by PAM increases with higher PAM to lymphocyte ratios.
- Accumulation of PAM in smokers' lungs may lead to significant local suppression of NK activity, potentially compromising lung defense.