Tumor necrosis factor-alpha-induced apoptosis in a human keratinocyte cell line (HaCaT) is counteracted by transforming growth factor-alpha

Pulmonary surfactant is a complex mixture of lipids and proteins that functions to keep alveoli from collapsing at the end of expiration. Dipalmitoylphosphatidylcholine has been identified as the most important component for lowering surface tension at the air-liquid interface. Hydrophobic surfactant apoproteins, SP-B and SP-C, play essential roles in the biophysical functions of the surfactant phospholipids. Hydrophilic surfactant apoproteins (SP-A and SP-D) that are members of C-type lectin superfamily, interact with phospholipids and glycolipids and modulate host defense functions in the lung. SP-A also plays an important role in regulating phospholipid homeostasis in the alveolar spaces. Recent advances in genetics and molecular biology have clarified the structure-function relationship of surfactant apoproteins.