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Updated: Aug 14, 2026
Assessing Anti-fungal Activity of Isolated Alveolar Macrophages by Confocal Microscopy
Published on: July 9, 2014
Characteristics of bovine alveolar macrophage elastase
Abstract:
Lavage of isolated bovine lung lobes was used to retrieve pulmonary alveolar macrophages (PAM). Nominal yields of 72 million viable PAM were routinely obtained using 500 ml of calcium- and magnesium-free phosphate-buffered saline. Bovine PAM readily attached to glass coverslips and within 24 hours, provided cell monolayers consisting exclusively of macrophages. Bovine PAM synthesized and secreted a calcium-dependent elastase in serum-free media. Optimal proteolytic activity using a radiolabeled elastin substrate was observed at pH 7.6. The elastase was insensitive to synthetic peptide chloromethyl ketone elastase inhibitors and to the serine protease inhibitor, phenylmethylsulfonyl fluoride. Enzyme activity, however, was effectively inhibited by the metal chelator, ethylenediaminetetraacetic acid, or suppressed by inhibition of protein synthesis with cycloheximide.
Insights
Researchers isolated bovine pulmonary alveolar macrophages (PAM) and discovered they secrete a calcium-dependent elastase. This enzyme
Area of Science:
- Pulmonary immunology
- Macrophage biology
- Enzymology
Background:
- Pulmonary alveolar macrophages (PAM) are critical immune cells in the lung.
- Understanding their functions, including enzyme secretion, is vital for respiratory health research.
Purpose of the Study:
- To isolate and characterize bovine pulmonary alveolar macrophages (PAM).
- To investigate the synthesis and properties of enzymes secreted by bovine PAM.
Main Methods:
- Bovine lung lobes were lavaged to retrieve PAM.
- Cells were cultured on glass coverslips to form monolayers.
- Elastase activity was measured using a radiolabeled elastin substrate under various conditions.
Main Results:
- High yields of viable bovine PAM were obtained.
- Bovine PAM formed pure macrophage monolayers.
- A calcium-dependent elastase was synthesized and secreted.
- Optimal elastase activity occurred at pH 7.6.
- The enzyme was insensitive to certain inhibitors but sensitive to EDTA and cycloheximide.
Conclusions:
- Bovine PAM can be readily isolated and cultured.
- Bovine PAM secrete a novel calcium-dependent elastase with unique inhibitory properties.
- This elastase may play a role in lung physiology or pathology.
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