Host defense functions of pulmonary surfactant.
Surfactant is a complex of lipids and proteins that reduces surface tension at the air/liquid interface of the lung and regulates immune cell function. Surfactant immune function is primarily attributed to two proteins: SP-A and SP-D. SP-A and SP-D are members of a protein family known as 'collectins', which are distinguished by their N-terminal collagen-like region and their C-terminal lectin domain. The lectin domain binds preferentially to sugars on the surface of pathogens and thereby opsonizes them for uptake by phagocytes. The collectins also modulate the functions of cells of the adaptive immune network including dendritic cells and T lymphocytes. In addition, recent studies show that bacterial products degrade surfactant. In summary, surfactant plays an important role in lung host defense. Surfactant degradation or inactivation may contribute to enhanced susceptibility to lung inflammation and infection.
Wright
Jo Rae
JR
Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA. j.wright@cellbio.duke.edu
D006801:Humans; D007109:Immunity; D007239:Infections / Q000276:immunology; D007249:Inflammation / Q000276:immunology; D008168:Lung / Q000276:immunology; D008171:Lung Diseases / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A / Q000502:physiology; D037663:Pulmonary Surfactant-Associated Protein D / Q000502:physiology; D037661:Pulmonary Surfactant-Associated Proteins / Q000032:analysis / Q000502:physiology*; D011663:Pulmonary Surfactants
D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants