Functions of surfactant proteins B and C

SP-B is the only surfactant-associated protein absolutely required for post natal lung function and survival. Complete deficiency of SP-B in mice and h umans results in lethal, neonatal respiratory distress syndrome and is char acterized by a virtual absence of lung compliance, highly disorganized lame llar bodies, and greatly diminished levels of SP-C mature peptide; in contr ast, lung structure and function in SP-C null mice is normal. This review a ttempts to integrate recent findings in humans and transgenic mice with the results of in vitro studies to provide a better understanding of the funct ions of SP-B and SP-C and the structural basis for their actions.