Bombesin in human and guinea pig alveolar macrophages

Bombesin found in neuroepithelial bodies and oat cell carcinoma of the lung, is thought to play an important role in normally developing and malignant lung. Monocytes-macrophages and human small cell lung carcinoma cells share several features, including macrophage-specific surface markers and the expression of functional receptors for bombesin-like neuropeptides and growth factors. Because small cell lung carcinoma cells synthesize immunoreactive bombesin, we investigated the possibility that alveolar macrophages also contain bombesin, a plausible hypothesis considering the many reports of neuropeptide production by immune cells and cells of bone marrow origin. Adherent human peripheral blood mononuclear cells as well as human and guinea pig alveolar macrophages were found to contain bombesin. The peptide was detected by radioimmunoassay, immunohistochemistry, high-pressure liquid chromatography with the use of different monospecific antibodies.