scholarly journals Surfactant protein D binding to alveolar macrophages

1994 ◽  
Vol 300 (1) ◽  
pp. 237-242 ◽  
Author(s):  
K Miyamura ◽  
L E A Leigh ◽  
J Lu ◽  
J Hopkin ◽  
A López Bernal ◽  
...  
Keyword(s):  
Alveolar Macrophages ◽  
Serum Proteins ◽  
Specific Binding ◽  
Lectin Binding ◽  
Protein A ◽  
Direct Interaction ◽  
Surfactant Protein ◽  
Lung Epithelial Cells ◽  
Surfactant Protein D ◽  
Apparent Dissociation Constant

Surfactant protein D (SP-D) is a lung-specific protein, synthesized and secreted by lung epithelial cells. It belongs to group III of the family of C-type lectins; each member of this group has an unusual overall structure consisting of multiple globular ‘head’ regions (which contain the C-type lectin domains) linked by triple-helical, collagen-like, strands. This group includes the surfactant protein A (SP-A) and the serum proteins mannan-binding protein, conglutinin and collectin-43, all of which have been shown to bind to the C1q receptor found on a wide variety of cells, including macrophages. Both SP-D and SP-A have been shown to enhance oxygen radical production by alveolar macrophages. Although this strongly suggests a direct interaction between SP-D and a specific receptor on alveolar macrophages, it is still unclear whether SP-D binds to the same receptor used by SP-A and/or C1q. Human SP-D was isolated from amniotic fluid and was radiolabelled using 125I. Alveolar macrophages were isolated from human bronchioalveolar lavage fluid, and also from bovine lung washings, by differential adhesion to 24-well tissue-culture plates. The study was carried out using EDTA-containing buffers, to eliminate Ca(2+)-dependent C-type lectin binding, and was also carried out at 4 degrees C to eliminate possible internalization by the cells. 125I-SP-D showed specific binding to alveolar macrophages in both a time- and concentration-saturable manner. The binding was inhibited, by approx. 90%, on addition of a 200-fold excess of unlabelled SP-D. The apparent dissociation constant (Kd) was (3.6 +/- 1.3) x 10(-11) M, based on the assumption that native SP-D is assembled as a dodecamer of 12 identical polypeptides of 43 kDa to yield a protein of 516 kDa. C1q was also shown to bind alveolar macrophages (Kd 3 x 10(-6) M), but addition of C1q did not show inhibition of the binding of 125I-SP-D to the macrophages. We conclude that SP-D binds specifically to alveolar macrophages and the receptor involved is different from that utilized by C1q.

scholarly journals Rat surfactant protein D enhances the production of oxygen radicals by rat alveolar macrophages

1992 ◽  
Vol 286 (1) ◽  
pp. 5-8 ◽  
Author(s):  
J F Van Iwaarden ◽  
H Shimizu ◽  
P H M Van Golde ◽  
D R Voelker ◽  
L M G Van Golde
Keyword(s):  
Alveolar Macrophages ◽  
Oxygen Radicals ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Surfactant Protein D ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Oxygen Radical Production ◽  
Stimulation Of

Rat surfactant protein D (SP-D) was shown to enhance the production of oxygen radicals by rat alveolar macrophages. This enhancement, which was determined by a lucigenin-dependent chemiluminescence assay, was maximal after 18 min at an SP-D concentration of 0.2 micrograms/ml. Surfactant lipids did not influence the stimulation of alveolar macrophages by SP-D, whereas the oxygen-radical production of these cells induced by surfactant protein A was inhibited by the lipids in a concentration-dependent manner.

Surfactant protein A, but not surfactant protein D, is an opsonin for influenza A virus phagocytosis by rat alveolar macrophages

1997 ◽  
Vol 27 (4) ◽  
pp. 886-890 ◽  
Author(s):  
Cornelis A. Benne ◽  
Barry Benaissa-Trouw ◽  
Jos A. G. Van Strijp ◽  
Cornelis A. Kraaijeveld ◽  
J. Freek F. Van Iwaarden
Keyword(s):  
Influenza A Virus ◽  
Alveolar Macrophages ◽  
Influenza A ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Surfactant Protein D

scholarly journals Binding of human collectins (SP-A and MBP) to influenza virus

1994 ◽  
Vol 304 (2) ◽  
pp. 455-461 ◽  
Author(s):  
R Malhotra ◽  
J S Haurum ◽  
S Thiel ◽  
R B Sim
Keyword(s):  
Influenza Virus ◽  
Serum Proteins ◽  
Protein A ◽  
Surfactant Protein ◽  
Influenza Viruses ◽  
Surfactant Protein D ◽  
Lectin Domain ◽  
Associated Proteins ◽  
Haemagglutinating Activity ◽  
Ligand Blot

Collectins are a group of soluble proteins each of which has collagenous domains and non-collagenous globular domains, the latter containing the consensus residues found in C-type lectins. Members of the collectin family are the serum proteins mannan-binding protein (MBP), conglutinin, CL-43, and the lung-associated proteins surfactant protein A (SP-A) and surfactant protein D (SP-D). MBP and conglutinin have been shown previously to bind to influenza viruses and to inhibit the infectivity and haemagglutinating activity of influenza viruses. We report here that the lung protein SP-A, like MBP, can bind to influenza virus (strain A/X31) through its lectin domain and inhibit the virus-mediated agglutination of red cells. The binding of SP-A or MBP to influenza virus was saturable, concentration-dependent, and required the presence of Ca2+ ions. Ligand-blot analysis, using MBP as ligand, of the virus lysate indicated that MBP binds to a 68 kDa viral species. The 68 kDa species was isolated to homogeneity and was shown to be the viral neuraminidase. The purified 68 kDa species inhibited the binding of both MBP and SP-A to influenza virus.

Specific binding of surfactant apoprotein SP-A to rat alveolar macrophages

1992 ◽  
Vol 262 (4) ◽  
pp. L412-L417 ◽  
Author(s):  
U. Pison ◽  
J. R. Wright ◽  
S. Hawgood
Keyword(s):  
Alveolar Macrophages ◽  
Specific Binding ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Dose Dependent Fashion ◽  
Type V ◽  
Dose Dependent ◽  
Surfactant Apoprotein

Surfactant protein A (SP-A) influences the function of alveolar macrophages in vitro. In this study the characteristics of the binding of 125I-labeled SP-A to rat alveolar macrophages has been investigated. The binding of SP-A to alveolar macrophages at 4 degrees C was saturable with half-maximal binding at a SP-A concentration of 4 micrograms/ml. Bound SP-A was rapidly displaced by an excess of unlabeled SP-A. The binding of labeled SP-A to the alveolar macrophages was blocked in a dose-dependent fashion by unlabeled SP-A, the collagen-like protein C1q and type V collagen but not by bovine serum albumin. These results suggest that a component of the interaction between SP-A and alveolar macrophages is mediated through the collagen-like domain of SP-A and that the characteristics of this interaction are consistent with there being a specific receptor for SP-A on the surface of alveolar macrophages.

scholarly journals A novel procedure for the rapid isolation of surfactant protein A with retention of its alveolar-macrophage-stimulating properties

1995 ◽  
Vol 309 (2) ◽  
pp. 551-555 ◽  
Author(s):  
J F van Iwaarden ◽  
F Teding van Berkhout ◽  
J A Whitsett ◽  
R S Oosting ◽  
L M G van Golde
Keyword(s):  
Alveolar Macrophage ◽  
Alveolar Macrophages ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Normal Rat ◽  
Normal Human ◽  
Novel Method ◽  
Alveolar Proteinosis ◽  
Simplex Virus

Previous studies have shown that surfactant protein A (SP-A) derived from alveolar-proteinosis patients activates rat alveolar macrophages. However, it is not known if normal rat, dog and human SP-A can also stimulate alveolar macrophages. As alveolar-proteinosis SP-A has a slightly different structure from ordinary SP-A, it would be possible that the ascribed alveolar-macrophage-stimulating properties of SP-A are restricted to alveolar-proteinosis SP-A. To clarify this issue, we isolated SP-A from normal rat and dog pulmonary surfactants, using the same isolation technique commonly used for the isolation of alveolar-proteinosis SP-A, i.e. by butanol precipitation. In contrast with human alveolar-proteinosis SP-A, rat and dog SP-A obtained thus could not activate rat alveolar macrophages to produce oxygen radicals or enhance the phagocytosis of fluorescein isothiocyanate-labelled herpes simplex virus. However, rat, dog and normal human SP-A isolated by a novel method, involving extraction from pulmonary surfactant by using n-octyl beta-D-glucopyranoside and subsequent purification by cation-exchange chromatography, were able to elicit an oxidative burst in rat as well as normal human alveolar macrophages. In addition, dog and rat SP-A obtained thus stimulated the phagocytosis of herpes simplex virus by rat alveolar macrophages. These findings indicate that normal human, rat and dog SP-A have the same alveolar-macrophage-stimulating properties as human alveolar proteinosis SP-A. Dog and rat SP-A isolated by this novel method had the same Ca(2+)-dependent self-aggregation and lipid-aggregation properties as SP-A isolated by butanol precipitation. The new and milder isolation procedure yielded SP-A of high purity, as judged by SDS/PAGE and ELISA.

Surfactant protein A protects growing cells and reduces TNF-alpha activity from LPS-stimulated macrophages

1996 ◽  
Vol 271 (2) ◽  
pp. L310-L319 ◽  
Author(s):  
J. C. McIntosh ◽  
S. Mervin-Blake ◽  
E. Conner ◽  
J. R. Wright
Keyword(s):  
Host Defense ◽  
Alveolar Macrophages ◽  
Cell Function ◽  
Immune Cell ◽  
Protein A ◽  
Surfactant Protein ◽  
Alpha Activity ◽  
Tnf Alpha ◽  
Activated Macrophages ◽  
Immune Functions

In addition to its effect on surfactant lipids, surfactant protein (SP)-A promotes host defense. To define further the role of SP-A in regulating immune cell function, we evaluated the effect of SP-A on lipopolysaccharide (LPS)-activated alveolar macrophages in two settings. First, cocultured LPS-activated macrophages significantly inhibited lung fibroblast growth, but SP-A (added daily) attenuated this effect. Both LPS and SP-A acted via macrophages rather than directly on the fibroblasts, at least partially by affecting tumor necrosis factor (TNF)-alpha activity. TNF-alpha reproduced the growth suppression, anti-TNF-alpha antibodies attenuated the effect LPS-activated macrophages, and SP-A reduced TNF-alpha activity in conditioned medium. Second, SP-A reduced TNF-alpha activity in medium from isolated LPS-stimulated macrophages. The effects of SP-A were noted with or without serum, were dose-dependent and reversible, and were seen with two different serotypes of smooth LPS. Equimolar concentrations of immunoglobulin G and C1q had no effect. Thus SP-A both enhances host defense and modulates immune functions of alveolar macrophages.

Pulmonary dysfunction in neonatal SP-B-deficient mice

1997 ◽  
Vol 273 (4) ◽  
pp. L875-L882 ◽  
Author(s):  
Keisuke Tokieda ◽  
Jeffrey A. Whitsett ◽  
Jean C. Clark ◽  
Timothy E. Weaver ◽  
Kazushige Ikeda ◽  
...  
Keyword(s):  
Critical Role ◽  
Protein A ◽  
Surfactant Protein ◽  
Lung Compliance ◽  
Phospholipid Content ◽  
Surfactant Protein D ◽  
Intratracheal Administration ◽  
Lung Expansion ◽  
B Mice ◽  
Deficient Mice

Pulmonary function was assessed in newborn wild-type and homozygous and heterozygous surfactant protein B (SP-B)-deficient mice after birth. SP-B+/+ and SP-B+/− mice became well oxygenated and survived postnatally. Although lung compliance was decreased slightly in the SP-B+/− mice, lung volumes and compliances were decreased markedly in homozygous SP-B−/− mice. They died rapidly after birth, failing to inflate their lungs or oxygenate. SP-B proprotein was absent in the SP-B−/− mice and was reduced in the SP-B+/− mice, as assessed by Western analysis. Surfactant protein A, surfactant proprotein C, surfactant protein D, and surfactant phospholipid content in lungs from SP-B+/− and SP-B−/− mice were not altered. Lung saturated phosphatidylcholine and precursor incorporation into saturated phosphatidylcholine were not influenced by SP-B genotype. Intratracheal administration of perfluorocarbon resulted in lung expansion, oxygenation, and prolonged survival of SP-B−/− mice and in reduced lung compliance in SP-B+/+ and SP-B+/− mice. Lack of SP-B caused respiratory failure at birth, and decreased SP-B protein was associated with reduced lung compliance. These findings demonstrate the critical role of SP-B in perinatal adaptation to air breathing.

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