Biomaterial Database

Surfactant protein A stimulates phagocytosis of specific pulmonary pathogens by alveolar macrophages. 1996

M J Tino, and J R Wright

Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.

Surfactant protein A (SP-A) regulates alveolar macrophage function and has been implicated in the mediation of pulmonary host defense. Our goals were to characterize the interaction of SP-A with various pulmonary pathogens, to investigate the mechanism of SP-A-mediated phagocytosis using an assay that distinguishes bound from internalized bacteria by quenching the fluorescence of extracellular bacteria, and to examine further the interactions of SP-A and the structurally homologous protein complement component 1q (C1q) with alveolar macrophages and peripheral blood monocytes. We found that SP-A binds to and increases the phagocytosis of Haemophilus influenzae, Streptococcus pneumoniae, and Group A Streptococcus; SP-A aggregates only H. influenzae. SP-A neither binds to, aggregates, nor stimulates the phagocytosis of Pseudomonas aeruginosa. We have also found that bronchoalveolar lavage stimulates phagocytosis and that this stimulation is reduced by an anti-SP-A antibody. While the enhancement of phagocytosis by SP-A is inhibited in blood monocytes adhered to C1q-coated surfaces, which presumably clusters the C1q receptor on the basal surface of the cell, alveolar macrophages on C1q-coated slides show no significant change in their response to SP-A. In summary, SP-A stimulates the phagocytosis by alveolar macrophages of specific pulmonary pathogens to which it binds, but aggregation is not required for the effect. Additionally, the role of the C1q receptor in the response to SP-A may differ between monocytes and alveolar macrophages.

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D009000	Monocytes	Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.	Monocyte
D010587	Phagocytosis	The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).	Phagocytoses
D011510	Proteolipids	Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.
D011663	Pulmonary Surfactants	Substances and drugs that lower the SURFACE TENSION of the mucoid layer lining the PULMONARY ALVEOLI.	Surfactants, Pulmonary,Pulmonary Surfactant,Surfactant, Pulmonary
D001992	Bronchoalveolar Lavage Fluid	Washing liquid obtained from irrigation of the lung, including the BRONCHI and the PULMONARY ALVEOLI. It is generally used to assess biochemical, inflammatory, or infection status of the lung.	Alveolar Lavage Fluid,Bronchial Lavage Fluid,Lung Lavage Fluid,Bronchial Alveolar Lavage Fluid,Lavage Fluid, Bronchial,Lavage Fluid, Lung,Pulmonary Lavage Fluid,Alveolar Lavage Fluids,Bronchial Lavage Fluids,Bronchoalveolar Lavage Fluids,Lavage Fluid, Alveolar,Lavage Fluid, Bronchoalveolar,Lavage Fluid, Pulmonary,Lavage Fluids, Alveolar,Lavage Fluids, Bronchial,Lavage Fluids, Bronchoalveolar,Lavage Fluids, Lung,Lavage Fluids, Pulmonary,Lung Lavage Fluids,Pulmonary Lavage Fluids
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002448	Cell Adhesion	Adherence of cells to surfaces or to other cells.	Adhesion, Cell,Adhesions, Cell,Cell Adhesions
D006193	Haemophilus influenzae	A species of HAEMOPHILUS found on the mucous membranes of humans and a variety of animals. The species is further divided into biotypes I through VIII.	Bacterium influenzae,Coccobacillus pfeifferi,Haemophilus meningitidis,Hemophilus influenzae,Influenza-bacillus,Mycobacterium influenzae
D006358	Hot Temperature	Presence of warmth or heat or a temperature notably higher than an accustomed norm.	Heat,Hot Temperatures,Temperature, Hot,Temperatures, Hot