Keywords: type I cell; type II cell; surfactant; lipogenesisThe alveolar surface is covered by an epithelium composed of two main cell types (1, 2). Type I cells are large flat cells that cover ‫ف‬ 95% of the alveolar surface and through which gas exchange takes place, and their metabolic properties are just now being discovered (2). Type II cells have a distinct morphology with characteristic lamellar bodies, the intracellular storage form of pulmonary surfactant, and apical microvilli. Type II cells make and secrete pulmonary surfactant, and they proliferate to restore the epithelium after damage to the more sensitive type I cells. Type II cells also transport sodium and fluid from the apical to the basolateral surface and play an important role in innate immunity.Although methods for isolating and culturing adult rat and mouse type II cells and fetal human type II cells have been available for years, there has been limited success maintaining the differentiated functions of adult human alveolar epithelial cells in primary culture. In addition, there are no human cell lines that produce surfactant. H441 cells express surfactant protein (SP)-A and SP-B, whereas A549 cells do not express any of the surfactant proteins nor contain a higher percentage of surfactant phospholipids than fibroblasts (3). A variety of methods for

The lung is continuously exposed to bacteria and their products, and has developed a complex defense mechanism, including neutrophil recruitment. In mice, keratinocyte cell-derived chemokine and macrophage inflammatory protein-2 are the major chemokines for neutrophil recruitment into the lung. We have previously described a role for C-X-C chemokine (