Collectin

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Collectins (collagen-containing C-type lectins) are a part of the innate immune system. They form a family of collagenous Ca2+-dependent defense lectins, which are found in animals. Collectins are soluble pattern recognition receptors (PRRs). Their function is to bind to oligosaccharide structure or lipids that are on the surface of microorganisms. Like other PRRs they bind pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) of oligosaccharide origin. Binding of collectins to microorganisms may trigger elimination of microorganisms by aggregation, complement activation, opsonization, activation of phagocytosis, or inhibition of microbial growth. Other functions of collectins are modulation of inflammatory, allergic responses, adaptive immune system and clearance of apoptotic cells.

Contents

Structure

Functionally collectins are trimers. Monomeric subunit consists of four parts:

Recognition of specific parts of microorganism is mediated by CRD in presence of calcium. [1] [2] Affinity of interaction between microbes and collectins depends on the degree of collectin oligomerization and also on the density of ligands on the surface of the microbe. [3]

Types of collectins

Nine types of collectins have been defined:

CL-43, CL-46 and conglutinin are found in bovine.

Function

Aggregation

Collectins can bind to the surface of microorganisms and between carbohydrate ligands. Due to these properties, the interaction can result in aggregation. [5] [6]

Opsonization and activation of phagocytosis

Collectins can act as opsonins. There is a specific interaction between collectins and receptors on phagocytic cells which can lead to increased clearance of microorganisms. [7] [8] [9] MBL can bind to microorganisms and this interaction can lead to opsonization through complement activation, [10] or it can opsonize the microorganism directly. [11] SP-A and SP-D can also interact with microorganisms and phagocytic cells to enhance phagocytosis of the microorganism. [12]

Inhibition of microbial growth

Collectins have effect on microorganism survival. SP-A and SP-D can bind to LPS (lipopolysaccharide) of both Gram-negative and Gram-positive bacteria. SP-A and SP-D can increase permeability of Gram-negative bacterial cell membrane. [13]

Modulation of inflammatory responses

SP-A and SP-D can damp induction of inflammation by LPS or endotoxin. It can be caused by removing the LPS or by binding the LPS to CD14 receptor on macrophages that can block the inflammatory response. [14] [15] [16] SP-A can also bind to TLR2 (toll-like receptor 2). This interaction causes decrease of TNF-α (tumor necrosis factor-α) production by alveolar macrophages stimulated with peptidoglycan. [17] SP-A and SP-D can modulate cytokine production. They modulate the production of oxygen and nitrogen reactive species which are very important for phagocytic cells. [18] [19] [20] SP-A and SP-D has s function as chemoattractants for alveolar neutrophils and monocytes. [21] MBL can recognize peptidoglycan via N-acetylglucosamine. This interaction leads to inhibition of ligand-induced inflammatory by macrophage chemokine production. [22]

Modulation of the adaptive immune system

SP-A and SP-D can suppress activated T-lymphocytes and IL-2 (interleukin-2) production. [23] [24] SP-D increases bacterial antigen presentation by dendritic cells [25] whereas SP-A blocs differentation of the immature dendritic cells. [26]

Modulation of allergic response

Collectins SP-A and SP-D have anti-allergic effects: they inhibit IgE binding to allergens, decrease histamine release from basophils, and inhibit T-lymphocyte production in the late phase of the inflammation. [27] [28] [29]

Apoptosis

Collectins SP-A and SP-D enhance clearance of apoptotic cells by macrophages. [30] [31]

Complement activation

Collectins are linked with activation of lectin pathway of complement activation. At the beginning, there is a binding of collectin to PAMPs or DAMPs. Collectin MBL is involved in activation of the lectin complement pathway. [32] [33] There are three serine proteases, MASP-1, 2 and 3 (MBL-associated serine proteases), which participate in activation of the lectin pathway. MASP-2 has a cleavage activity and it is essential for forming lectin C3 and C5 convertases and for activation of the complement. [34] [35] [36]

Reviews

For more information and details see reviews: [37] [38] [39]

Related Research Articles

<span class="mw-page-title-main">Phagocytosis</span> Process by which a cell uses its plasma membrane to engulf a large particle

Phagocytosis is the process by which a cell uses its plasma membrane to engulf a large particle, giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte.

Opsonins are extracellular proteins that, when bound to substances or cells, induce phagocytes to phagocytose the substances or cells with the opsonins bound. Thus, opsonins act as tags to label things in the body that should be phagocytosed by phagocytes. Different types of things ("targets") can be tagged by opsonins for phagocytosis, including: pathogens, cancer cells, aged cells, dead or dying cells, excess synapses, or protein aggregates. Opsonins help clear pathogens, as well as dead, dying and diseased cells.

Pattern recognition receptors (PRRs) play a crucial role in the proper function of the innate immune system. PRRs are germline-encoded host sensors, which detect molecules typical for the pathogens. They are proteins expressed, mainly, by cells of the innate immune system, such as dendritic cells, macrophages, monocytes, neutrophils and epithelial cells, to identify two classes of molecules: pathogen-associated molecular patterns (PAMPs), which are associated with microbial pathogens, and damage-associated molecular patterns (DAMPs), which are associated with components of host's cells that are released during cell damage or death. They are also called primitive pattern recognition receptors because they evolved before other parts of the immune system, particularly before adaptive immunity. PRRs also mediate the initiation of antigen-specific adaptive immune response and release of inflammatory cytokines.

<span class="mw-page-title-main">DC-SIGN</span> Protein-coding gene in the species Homo sapiens

DC-SIGN also known as CD209 is a protein which in humans is encoded by the CD209 gene.

<span class="mw-page-title-main">Lectin pathway</span>

The lectin pathway or MBL pathway is a type of cascade reaction in the complement system, similar in structure to the classical complement pathway, in that, after activation, it proceeds through the action of C4 and C2 to produce activated complement proteins further down the cascade. In contrast to the classical complement pathway, the lectin pathway does not recognize an antibody bound to its target. The lectin pathway starts with mannose-binding lectin (MBL) or ficolin binding to certain sugars.

<span class="mw-page-title-main">MASP1 (protein)</span> Protein-coding gene in the species Homo sapiens

Mannan-binding lectin serine protease 1 also known as mannose-associated serine protease 1 (MASP-1) is an enzyme that in humans is encoded by the MASP1 gene.

<span class="mw-page-title-main">Mannan-binding lectin</span> Mammalian protein found in Homo sapiens

Mannose-binding lectin (MBL), also called mannan-binding lectin or mannan-binding protein (MBP), is a lectin that is instrumental in innate immunity as an opsonin and via the lectin pathway.

Siglecs(Sialic acid-binding immunoglobulin-type lectins) are cell surface proteins that bind sialic acid. They are found primarily on the surface of immune cells and are a subset of the I-type lectins. There are 14 different mammalian Siglecs, providing an array of different functions based on cell surface receptor-ligand interactions.

The mannose receptor is a C-type lectin primarily present on the surface of macrophages, immature dendritic cells and liver sinusoidal endothelial cells, but is also expressed on the surface of skin cells such as human dermal fibroblasts and keratinocytes. It is the first member of a family of endocytic receptors that includes Endo180 (CD280), M-type PLA2R, and DEC-205 (CD205).

<span class="mw-page-title-main">Surfactant protein D</span> Protein-coding gene in the species Homo sapiens

Surfactant protein D, also known as SP-D, is a lung surfactant protein part of the collagenous family of proteins called collectin. In humans, SP-D is encoded by the SFTPD gene and is part of the innate immune system. Each SP-D subunit is composed of an N-terminal domain, a collagenous region, a nucleating neck region, and a C-terminal lectin domain. Three of these subunits assemble to form a homotrimer, which further assemble into a tetrameric complex.

Surfactant protein A is an innate immune system collectin. It is water-soluble and has collagen-like domains similar to SP-D. It is part of the innate immune system and is used to opsonize bacterial cells in the alveoli marking them for phagocytosis by alveolar macrophages. SP-A may also play a role in negative feedback limiting the secretion of pulmonary surfactant. SP-A is not required for pulmonary surfactant to function but does confer immune effects to the organism.

<span class="mw-page-title-main">CD69</span>

CD69 is a human transmembrane C-Type lectin protein encoded by the CD69 gene. It is an early activation marker that is expressed in hematopoietic stem cells, T cells, and many other cell types in the immune system. It is also implicated in T cell differentiation as well as lymphocyte retention in lymphoid organs.

<span class="mw-page-title-main">Surfactant protein A1</span> Protein-coding gene in the species Homo sapiens

Surfactant protein A1(SP-A1), also known as Pulmonary surfactant-associated protein A1(PSP-A) is a protein that in humans is encoded by the SFTPA1 gene.

<span class="mw-page-title-main">CD93</span>

CD93 is a protein that in humans is encoded by the CD93 gene. CD93 is a C-type lectin transmembrane receptor which plays a role not only in cell–cell adhesion processes but also in host defense.

<span class="mw-page-title-main">Surfactant protein A2</span> Protein-coding gene in the species Homo sapiens

Surfactant protein A2(SP-A2), also known as Pulmonary surfactant-associated protein A2(PSP-A2) is a protein that in humans is encoded by the SFTPA2 gene.

The following outline is provided as an overview of and topical guide to immunology:

<span class="mw-page-title-main">C3a (complement)</span>

C3a is one of the proteins formed by the cleavage of complement component 3; the other is C3b. C3a is a 77 residue anaphylatoxin that binds to the C3a receptor (C3aR), a class A G protein-coupled receptor. It plays a large role in the immune response.

<span class="mw-page-title-main">Pulmonary surfactant protein D</span>

In molecular biology, Pulmonary surfactant protein D (SP-D) is a protein domain predominantly found in lung surfactant. This protein plays a special role; its primary task is to act as a defence protein against any pathogens that may invade the lung. It also plays a role in lubricating the lung and preventing it from collapse. It has an interesting structure as it forms a triple-helical parallel coiled coil, helps the protein to fold into a trimer.

Ficolins are pattern recognition receptors that bind to acetyl groups present in the carbohydrates of bacterial surfaces and mediate activation of the lectin pathway of the complement cascade.

Apoptotic-cell associated molecular patterns (ACAMPs) are molecular markers present on cells which are going through apoptosis, i.e. programmed cell death. The term was used for the first time by C. D. Gregory in 2000. Recognition of these patterns by the pattern recognition receptors (PRRs) of phagocytes then leads to phagocytosis of the apoptotic cell. These patterns include eat-me signals on the apoptotic cells, loss of don’t-eat-me signals on viable cells and come-get-me signals ) secreted by the apoptotic cells in order to attract phagocytes. Thanks to these markers, apoptotic cells, unlike necrotic cells, do not trigger the unwanted immune response.

References

  1. Weis, W I; G V Crichlow; H M Murthy; W A Hendrickson; K Drickamer (1991-11-05). "Physical characterization and crystallization of the carbohydrate-recognition domain of a mannose-binding protein from rat". The Journal of Biological Chemistry. 266 (31): 20678–20686. doi: 10.1016/S0021-9258(18)54762-1 . ISSN   0021-9258. PMID   1939118.
  2. Weis, W I; K Drickamer; W A Hendrickson (1992-11-12). "Structure of a C-type mannose-binding protein complexed with an oligosaccharide". Nature. 360 (6400): 127–134. Bibcode:1992Natur.360..127W. doi:10.1038/360127a0. ISSN   0028-0836. PMID   1436090. S2CID   4353217.
  3. Lee, R T; Y Ichikawa; M Fay; K Drickamer; M C Shao; Y C Lee (1991-03-15). "Ligand-binding characteristics of rat serum-type mannose-binding protein (MBP-A). Homology of binding site architecture with mammalian and chicken hepatic lectins". The Journal of Biological Chemistry. 266 (8): 4810–4815. doi: 10.1016/S0021-9258(19)67721-5 . ISSN   0021-9258. PMID   2002028.
  4. conglutinin at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
  5. Ferguson, J S; D R Voelker; F X McCormack; L S Schlesinger (1999-07-01). "Surfactant protein D binds to Mycobacterium tuberculosis bacilli and lipoarabinomannan via carbohydrate-lectin interactions resulting in reducedphagocytosis of the bacteria by macrophages". Journal of Immunology. 163 (1): 312–321. doi: 10.4049/jimmunol.163.1.312 . ISSN   0022-1767. S2CID   86321161.
  6. Schelenz, S; R Malhotra; R B Sim; U Holmskov; G J Bancroft (September 1995). "Binding of host collectins to the pathogenic yeast Cryptococcus neoformans: human surfactant protein D acts as an agglutinin for acapsular yeast cells". Infection and Immunity. 63 (9): 3360–3366. doi:10.1128/IAI.63.9.3360-3366.1995. ISSN   0019-9567. PMC   173462 . PMID   7642263.
  7. McNeely, T B; J D Coonrod (July 1994). "Aggregation and opsonization of type A but not type B Hemophilus influenzae by surfactant protein A". American Journal of Respiratory Cell and Molecular Biology. 11 (1): 114–122. doi:10.1165/ajrcmb.11.1.8018334. ISSN   1044-1549. PMID   8018334.
  8. O'Riordan, D M; J E Standing; K Y Kwon; D Chang; E C Crouch; A H Limper (June 1995). "Surfactant protein D interacts with Pneumocystis carinii and mediates organism adherence to alveolar macrophages". The Journal of Clinical Investigation. 95 (6): 2699–2710. doi:10.1172/JCI117972. ISSN   0021-9738. PMC   295953 . PMID   7769109.
  9. Ofek, I; A Mesika; M Kalina; Y Keisari; R Podschun; H Sahly; D Chang; D McGregor; E Crouch (January 2001). "Surfactant protein D enhances phagocytosis and killing of unencapsulated phase variants of Klebsiella pneumoniae". Infection and Immunity. 69 (1): 24–33. doi:10.1128/IAI.69.1.24-33.2001. ISSN   0019-9567. PMC   97851 . PMID   11119485.
  10. Holmskov, Uffe; Steffen Thiel; Jens C Jensenius (2003). "Collections and ficolins: humoral lectins of the innate immune defense". Annual Review of Immunology. 21: 547–578. doi:10.1146/annurev.immunol.21.120601.140954. ISSN   0732-0582. PMID   12524383.
  11. Kuhlman, M; K Joiner; R A Ezekowitz (1989-05-01). "The human mannose-binding protein functions as an opsonin". The Journal of Experimental Medicine. 169 (5): 1733–1745. doi:10.1084/jem.169.5.1733. ISSN   0022-1007. PMC   2189296 . PMID   2469767.
  12. Hartshorn, K L; E Crouch; M R White; M L Colamussi; A Kakkanatt; B Tauber; V Shepherd; K N Sastry (June 1998). "Pulmonary surfactant proteins A and D enhance neutrophil uptake of bacteria". The American Journal of Physiology. 274 (6 Pt 1): L958–969. doi:10.1152/ajplung.1998.274.6.L958. ISSN   0002-9513. PMID   9609735.
  13. Wu, Huixing; Alexander Kuzmenko; Sijue Wan; Lyndsay Schaffer; Alison Weiss; James H Fisher; Kwang Sik Kim; Francis X McCormack (May 2003). "Surfactant proteins A and D inhibit the growth of Gram-negative bacteria by increasing membrane permeability". The Journal of Clinical Investigation. 111 (10): 1589–1602. doi:10.1172/JCI16889. ISSN   0021-9738. PMC   155045 . PMID   12750409.
  14. van Rozendaal, B A; C H van de Lest; M van Eijk; L M van Golde; W F Voorhout; H P van Helden; H P Haagsman (1999-08-30). "Aerosolized endotoxin is immediately bound by pulmonary surfactant protein D in vivo". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1454 (3): 261–269. doi: 10.1016/s0925-4439(99)00042-3 . ISSN   0006-3002. PMID   10452960.
  15. Borron, P; J C McIntosh; T R Korfhagen; J A Whitsett; J Taylor; J R Wright (April 2000). "Surfactant-associated protein A inhibits LPS-induced cytokine and nitric oxide production in vivo". American Journal of Physiology. Lung Cellular and Molecular Physiology. 278 (4): L840–847. doi:10.1152/ajplung.2000.278.4.l840. ISSN   1040-0605. PMID   10749762. S2CID   25269338.
  16. Sano, H; H Chiba; D Iwaki; H Sohma; D R Voelker; Y Kuroki (2000-07-21). "Surfactant proteins A and D bind CD14 by different mechanisms". The Journal of Biological Chemistry. 275 (29): 22442–22451. doi: 10.1074/jbc.M001107200 . ISSN   0021-9258. PMID   10801802.
  17. Murakami, Seiji; Daisuke Iwaki; Hiroaki Mitsuzawa; Hitomi Sano; Hiroki Takahashi; Dennis R Voelker; Toyoaki Akino; Yoshio Kuroki (2002-03-01). "Surfactant protein A inhibits peptidoglycan-induced tumor necrosis factor-alpha secretion in U937 cells and alveolar macrophages by direct interaction with toll-like receptor 2". The Journal of Biological Chemistry. 277 (9): 6830–6837. doi: 10.1074/jbc.M106671200 . ISSN   0021-9258. PMID   11724772.
  18. Tino, M J; J R Wright (1998-11-19). "Interactions of surfactant protein A with epithelial cells and phagocytes". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1408 (2–3): 241–263. doi: 10.1016/s0925-4439(98)00071-4 . ISSN   0006-3002. PMID   9813349.
  19. Wright, J R (October 1997). "Immunomodulatory functions of surfactant". Physiological Reviews. 77 (4): 931–962. doi:10.1152/physrev.1997.77.4.931. ISSN   0031-9333. PMID   9354809.
  20. Crouch, E; J R Wright (2001). "Surfactant proteins a and d and pulmonary host defense". Annual Review of Physiology. 63: 521–554. doi:10.1146/annurev.physiol.63.1.521. ISSN   0066-4278. PMID   11181966.
  21. Tino, M J; J R Wright (January 1999). "Surfactant proteins A and D specifically stimulate directed actin-based responses in alveolar macrophages". The American Journal of Physiology. 276 (1 Pt 1): L164–174. doi:10.1152/ajplung.1999.276.1.L164. ISSN   0002-9513. PMID   9887069.
  22. Nadesalingam, Jeya; Alister W Dodds; Kenneth B M Reid; Nades Palaniyar (2005-08-01). "Mannose-binding lectin recognizes peptidoglycan via the N-acetyl glucosamine moiety, and inhibits ligand-induced proinflammatory effect and promotes chemokine production by macrophages". Journal of Immunology. 175 (3): 1785–1794. doi: 10.4049/jimmunol.175.3.1785 . ISSN   0022-1767. PMID   16034120.
  23. Borron, P; F X McCormack; B M Elhalwagi; Z C Chroneos; J F Lewis; S Zhu; J R Wright; V L Shepherd; F Possmayer; K Inchley; L J Fraher (October 1998). "Surfactant protein A inhibits T cell proliferation via its collagen-like tail and a 210-kDa receptor". The American Journal of Physiology. 275 (4 Pt 1): L679–686. doi:10.1152/ajplung.1998.275.4.L679. ISSN   0002-9513. PMID   9755099.
  24. Borron, P J; E C Crouch; J F Lewis; J R Wright; F Possmayer; L J Fraher (1998-11-01). "Recombinant rat surfactant-associated protein D inhibits human T lymphocyte proliferation and IL-2 production". Journal of Immunology. 161 (9): 4599–4603. doi: 10.4049/jimmunol.161.9.4599 . ISSN   0022-1767. PMID   9794387. S2CID   26563431.
  25. Brinker, K G; E Martin; P Borron; E Mostaghel; C Doyle; C V Harding; J R Wright (December 2001). "Surfactant protein D enhances bacterial antigen presentation by bone marrow-derived dendritic cells". American Journal of Physiology. Lung Cellular and Molecular Physiology. 281 (6): L1453–1463. doi:10.1152/ajplung.2001.281.6.l1453. ISSN   1040-0605. PMID   11704542. S2CID   1356964.
  26. Brinker, Karen G; Hollie Garner; Jo Rae Wright (January 2003). "Surfactant protein A modulates the differentiation of murine bone marrow-derived dendritic cells". American Journal of Physiology. Lung Cellular and Molecular Physiology. 284 (1): L232–241. doi:10.1152/ajplung.00187.2002. ISSN   1040-0605. PMID   12388334.
  27. Strong, P; K B M Reid; H Clark (October 2002). "Intranasal delivery of a truncated recombinant human SP-D is effective at down-regulating allergic hypersensitivity in mice sensitized to allergens of Aspergillus fumigatus". Clinical and Experimental Immunology. 130 (1): 19–24. doi:10.1046/j.1365-2249.2002.01968.x. ISSN   0009-9104. PMC   1906502 . PMID   12296848.
  28. Wang, J Y; U Kishore; B L Lim; P Strong; K B Reid (November 1996). "Interaction of human lung surfactant proteins A and D with mite (Dermatophagoides pteronyssinus) allergens". Clinical and Experimental Immunology. 106 (2): 367–373. doi:10.1046/j.1365-2249.1996.d01-838.x. ISSN   0009-9104. PMC   2200585 . PMID   8918587.
  29. Wang, J Y; C C Shieh; P F You; H Y Lei; K B Reid (August 1998). "Inhibitory effect of pulmonary surfactant proteins A and D on allergen-induced lymphocyte proliferation and histamine release in children with asthma". American Journal of Respiratory and Critical Care Medicine. 158 (2): 510–518. doi:10.1164/ajrccm.158.2.9709111. ISSN   1073-449X. PMID   9700129.
  30. Vandivier, R William; Carol Anne Ogden; Valerie A Fadok; Peter R Hoffmann; Kevin K Brown; Marina Botto; Mark J Walport; James H Fisher; Peter M Henson; Kelly E Greene (2002-10-01). "Role of surfactant proteins A, D, and C1q in the clearance of apoptotic cells in vivo and in vitro: calreticulin and CD91 as a common collectin receptor complex". Journal of Immunology. 169 (7): 3978–3986. doi: 10.4049/jimmunol.169.7.3978 . ISSN   0022-1767. PMID   12244199.
  31. Schagat, T L; J A Wofford; J R Wright (2001-02-15). "Surfactant protein A enhances alveolar macrophage phagocytosis of apoptotic neutrophils". Journal of Immunology. 166 (4): 2727–2733. doi: 10.4049/jimmunol.166.4.2727 . ISSN   0022-1767. PMID   11160338.
  32. Schwaeble, Wilhelm; Mads R Dahl; Steffen Thiel; Cordula Stover; Jens C Jensenius (September 2002). "The mannan-binding lectin-associated serine proteases (MASPs) and MAp19: four components of the lectin pathway activation complex encoded by two genes". Immunobiology. 205 (4–5): 455–466. doi:10.1078/0171-2985-00146. ISSN   0171-2985. PMID   12396007.
  33. Fujita, Teizo (May 2002). "Evolution of the lectin-complement pathway and its role in innate immunity". Nature Reviews. Immunology. 2 (5): 346–353. doi:10.1038/nri800. ISSN   1474-1733. PMID   12033740. S2CID   24314003.
  34. Schwaeble, Wilhelm; Mads R Dahl; Steffen Thiel; Cordula Stover; Jens C Jensenius (September 2002). "The mannan-binding lectin-associated serine proteases (MASPs) and MAp19: four components of the lectin pathway activation complex encoded by two genes". Immunobiology. 205 (4–5): 455–466. doi:10.1078/0171-2985-00146. ISSN   0171-2985. PMID   12396007.
  35. Thiel, S; T Vorup-Jensen; C M Stover; W Schwaeble; S B Laursen; K Poulsen; A C Willis; P Eggleton; S Hansen; U Holmskov; K B Reid; J C Jensenius (1997-04-03). "A second serine protease associated with mannan-binding lectin that activates complement". Nature. 386 (6624): 506–510. Bibcode:1997Natur.386..506T. doi:10.1038/386506a0. ISSN   0028-0836. PMID   9087411. S2CID   4261967.
  36. Schwaeble, Wilhelm J; Nicholas J Lynch; James E Clark; Michael Marber; Nilesh J Samani; Youssif Mohammed Ali; Thomas Dudler; Brian Parent; Karl Lhotta; Russell Wallis; Conrad A Farrar; Steven Sacks; Haekyung Lee; Ming Zhang; Daisuke Iwaki; Minoru Takahashi; Teizo Fujita; Clark E Tedford; Cordula M Stover (2011-05-03). "Targeting of mannan-binding lectin-associated serine protease-2 confers protection from myocardial and gastrointestinal ischemia/reperfusion injury". Proceedings of the National Academy of Sciences of the United States of America. 108 (18): 7523–7528. Bibcode:2011PNAS..108.7523S. doi: 10.1073/pnas.1101748108 . ISSN   1091-6490. PMC   3088599 . PMID   21502512.
  37. van de Wetering, J Koenraad; Lambert M G van Golde; Joseph J Batenburg (April 2004). "Collectins: players of the innate immune system". European Journal of Biochemistry. 271 (7): 1229–1249. doi: 10.1111/j.1432-1033.2004.04040.x . ISSN   0014-2956. PMID   15030473.
  38. Gupta, Garima; Avadhesha Surolia (May 2007). "Collectins: sentinels of innate immunity". BioEssays. 29 (5): 452–464. doi:10.1002/bies.20573. ISSN   0265-9247. PMID   17450595. S2CID   38069549.
  39. Nayak, Annapurna; Eswari Dodagatta-Marri; Anthony George Tsolaki; Uday Kishore (2012). "An Insight into the Diverse Roles of Surfactant Proteins, SP-A and SP-D in Innate and Adaptive Immunity". Frontiers in Immunology. 3: 131. doi: 10.3389/fimmu.2012.00131 . ISSN   1664-3224. PMC   3369187 . PMID   22701116.