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Updated: Aug 23, 2026

Flow Cytometric Isolation of Primary Murine Type II Alveolar Epithelial Cells for Functional and Molecular Studies
Published on: December 26, 2012
Host defense functions of pulmonary surfactant
1Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA. j.wright@cellbio.duke.edu
Abstract:
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.
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