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An Insight into the Diverse Roles of Surfactant Proteins, SP-A and SP-D in Innate and Adaptive Immunity.

Nayak A, Dodagatta-Marri E, Tsolaki AG, Kishore U - Front Immunol (2012)

Bottom Line: These proteins bind to target ligands on pathogens, allergens, and apoptotic cells, via C-terminal homotrimeric carbohydrate recognition domains, while the collagen region brings about the effector functions via its interaction with cell surface receptors.SP-A and SP-D deal with various pathogens, using a range of innate immune mechanisms such as agglutination/aggregation, enhancement of phagocytosis, and killing mechanisms by phagocytic cells and direct growth inhibition.This review enumerates immunological properties of SP-A and SP-D inside and outside lungs and discusses their importance in human health and disease.

View Article: PubMed Central - PubMed

Affiliation: Centre for Infection, Immunity and Disease Mechanisms, School of Health Sciences and Social Care, Brunel University London, UK.

ABSTRACT
Surfactant proteins SP-A and SP-D are hydrophilic, collagen-containing calcium-dependent lectins, which appear to have a range of innate immune functions at pulmonary as well as extrapulmonary sites. These proteins bind to target ligands on pathogens, allergens, and apoptotic cells, via C-terminal homotrimeric carbohydrate recognition domains, while the collagen region brings about the effector functions via its interaction with cell surface receptors. SP-A and SP-D deal with various pathogens, using a range of innate immune mechanisms such as agglutination/aggregation, enhancement of phagocytosis, and killing mechanisms by phagocytic cells and direct growth inhibition. SP-A and SP-D have also been shown to be involved in the control of pulmonary inflammation including allergy and asthma. Emerging evidence suggest that SP-A and SP-D are capable of linking innate immunity with adaptive immunity that includes modulation of dendritic cell function and helper T cell polarization. This review enumerates immunological properties of SP-A and SP-D inside and outside lungs and discusses their importance in human health and disease.

No MeSH data available.


Related in: MedlinePlus

Illustration of a molecule of (A) SP-A and (B) SP-D depicting different regions. The molecules are first shown as monomers and trimers. They are divided into four subunits, the N-terminal non-collagenous domain, collagenous region, helical neck, and C-terminal carbohydrate recognition domain. Each sub-unit has different ligand binding affinities.
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Figure 1: Illustration of a molecule of (A) SP-A and (B) SP-D depicting different regions. The molecules are first shown as monomers and trimers. They are divided into four subunits, the N-terminal non-collagenous domain, collagenous region, helical neck, and C-terminal carbohydrate recognition domain. Each sub-unit has different ligand binding affinities.

Mentions: SP-A and SP-D are large hydrophilic proteins, as opposed to SP-B and SP-C, the other two hydrophobic surfactant proteins found in the lungs. Their primary structure is organized into a cysteine-containing N-terminal region, a triple-helical collagen region composed of repeating Gly-X-Y triplets, an α-helical coiled-coil neck region, and a C-terminus comprising a C-type lectin or CRD region (reviewed in Kishore et al., 2006). SP-A and SP-D are large oligomeric structures, each assembled from multiple copies of either one or two polypeptide chains. SP-A has a hexameric structure in which six structural subunits associate to form a molecule of 630 kDa made up of 18 chains. SP-D is composed of oligomers of a 130 kDa subunit comprising three identical polypeptide chains of 43 kDa. Human SP-D is assembled into a 520 kDa tetrameric structure with four of the homotrimeric subunits linked via their N-terminal regions, but multimers, trimers, dimers and monomers are also possible (Holmskov et al., 2003; Kishore et al., 2006; Figures 1A,B).


An Insight into the Diverse Roles of Surfactant Proteins, SP-A and SP-D in Innate and Adaptive Immunity.

Nayak A, Dodagatta-Marri E, Tsolaki AG, Kishore U - Front Immunol (2012)

Illustration of a molecule of (A) SP-A and (B) SP-D depicting different regions. The molecules are first shown as monomers and trimers. They are divided into four subunits, the N-terminal non-collagenous domain, collagenous region, helical neck, and C-terminal carbohydrate recognition domain. Each sub-unit has different ligand binding affinities.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3369187&req=5

Figure 1: Illustration of a molecule of (A) SP-A and (B) SP-D depicting different regions. The molecules are first shown as monomers and trimers. They are divided into four subunits, the N-terminal non-collagenous domain, collagenous region, helical neck, and C-terminal carbohydrate recognition domain. Each sub-unit has different ligand binding affinities.
Mentions: SP-A and SP-D are large hydrophilic proteins, as opposed to SP-B and SP-C, the other two hydrophobic surfactant proteins found in the lungs. Their primary structure is organized into a cysteine-containing N-terminal region, a triple-helical collagen region composed of repeating Gly-X-Y triplets, an α-helical coiled-coil neck region, and a C-terminus comprising a C-type lectin or CRD region (reviewed in Kishore et al., 2006). SP-A and SP-D are large oligomeric structures, each assembled from multiple copies of either one or two polypeptide chains. SP-A has a hexameric structure in which six structural subunits associate to form a molecule of 630 kDa made up of 18 chains. SP-D is composed of oligomers of a 130 kDa subunit comprising three identical polypeptide chains of 43 kDa. Human SP-D is assembled into a 520 kDa tetrameric structure with four of the homotrimeric subunits linked via their N-terminal regions, but multimers, trimers, dimers and monomers are also possible (Holmskov et al., 2003; Kishore et al., 2006; Figures 1A,B).

Bottom Line: These proteins bind to target ligands on pathogens, allergens, and apoptotic cells, via C-terminal homotrimeric carbohydrate recognition domains, while the collagen region brings about the effector functions via its interaction with cell surface receptors.SP-A and SP-D deal with various pathogens, using a range of innate immune mechanisms such as agglutination/aggregation, enhancement of phagocytosis, and killing mechanisms by phagocytic cells and direct growth inhibition.This review enumerates immunological properties of SP-A and SP-D inside and outside lungs and discusses their importance in human health and disease.

View Article: PubMed Central - PubMed

Affiliation: Centre for Infection, Immunity and Disease Mechanisms, School of Health Sciences and Social Care, Brunel University London, UK.

ABSTRACT
Surfactant proteins SP-A and SP-D are hydrophilic, collagen-containing calcium-dependent lectins, which appear to have a range of innate immune functions at pulmonary as well as extrapulmonary sites. These proteins bind to target ligands on pathogens, allergens, and apoptotic cells, via C-terminal homotrimeric carbohydrate recognition domains, while the collagen region brings about the effector functions via its interaction with cell surface receptors. SP-A and SP-D deal with various pathogens, using a range of innate immune mechanisms such as agglutination/aggregation, enhancement of phagocytosis, and killing mechanisms by phagocytic cells and direct growth inhibition. SP-A and SP-D have also been shown to be involved in the control of pulmonary inflammation including allergy and asthma. Emerging evidence suggest that SP-A and SP-D are capable of linking innate immunity with adaptive immunity that includes modulation of dendritic cell function and helper T cell polarization. This review enumerates immunological properties of SP-A and SP-D inside and outside lungs and discusses their importance in human health and disease.

No MeSH data available.


Related in: MedlinePlus