SP-C Protection 

Cellular Antiendotoxin Activities of Lung Surfactant Protein C in Lipid Vesicles. Augusto, Luis A.. Amer J of Resp & Crit Care Med (Aug 2003) 68; 335-341.

 Bacterial lipopolyssacharides (LPS) is a component of the gram-negative bacterial cell wall that is released in vivo into the circulation during infection and sepsis. A common clinical complication of sepsis is lung injury, with frequent development of an acute respiratory distress syndrome. 

The lung has efficient defense mechanisms against LPS under normal exposure conditions. When LPS carried by gram-negative bacteria or dust reaches the alveolar spaces at the terminal airways, it encounters a surfactant layer that covers the epithelium and consists of lipids and surfactant associated proteins. 

It has been established that the two hydrophilic surfactant proteins (SP) A and SP-D are important in pulmonary host defense. Not only because they bind and aggregate various microorganisms, but also because they bind LPS and modulate LPS-triggered responses.

 The two hydrophobic surfactant proteins SP-B and SP-C are considered critical for the absorption and spreading of the surfactant film at the air-liquid interface. But their possible role in lung defense remains elusive.  They established that SP-C, but not SP-B, can bind to the lipid A region of LPS’s  of various phenotypes. Helping to protect the lung.

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