von Dr. Marcus Gereke
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| [1.] Mag/Fragment 022 01 - Diskussion Zuletzt bearbeitet: 2014-03-10 12:10:33 Graf Isolan | Fragment, Gesichtet, Mag, SMWFragment, Schutzlevel sysop, Verschleierung, Wright 2005 |
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| Untersuchte Arbeit: Seite: 22, Zeilen: 1-32 |
Quelle: Wright 2005 Seite(n): 64, Zeilen: l.col: 5ff |
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| Through the carbohydrate-recognition domains (CRD) and the collagen-like regions it is possible for SP-A and SP-D, as well as MBL, to bind DNA from a variety of origins, including mice and bacteria (Palaniyar et al., 2004). SP-D effectively binds and aggregates alveolar macrophages DNA and it enhances the uptake of DNA by human monocytic cells (Palaniyar et al., 2003). Binding of the collectins to cell-surface DNA might be one mechanism by which they mediate enhanced phagocytosis of apoptotic cells.
Uptake of apoptotic cells by macrophages results in release of anti-inflammatory mediators, such as transforming growth factors-β (TGF-β), IL-10 and prostaglandin E2 (Fadok et al., 1998). This response is in contrast to the release of pro-inflammatory cytokines that occurs when phagocytes ingest microorganisms. In addition to enhancing the uptake of apoptotic cells, SP-A also enhances the release of TGF-β by macrophages (Reidy and Wright, 2003), indicating that SP-A can promote resolution of inflammation at several levels of the apoptotic-cell clearance process and that surfactant proteins can indirectly induce anti-inflammatory responses by phagocytes. As discussed above, surfactant is linked to innate immunity. However, surfactant is also linked to adaptive immunity in the lung by modulating functions of both dendritic cells and T cells. It has been shown that SP-A and SP-D have different effects on DC functions. The uptake and presentation of antigens is enhanced by SP-D (Brinker et al., 2001), but only SP-A can inhibit maturation of DC, as assessed by cell-surface marker expression, and functional activity, such as phagocytosis and chemotaxis (Brinker et al., 2003). The proliferation of T cells stimulated with plant lectins, CD3-specific antibodies or phorbol esters is inhibited by SP-A and SP-D. It has been suggested that the inhibition of IL-2 production might mediate this process (Borron et al., 1996; Borron et al, 1998). In addition, both the collagen-like region and the CRD of SP-A have been implicated in the inhibition of lymphocyte function, probably due to inhibition of calcium signalling (Borron et al., 2002). These data indicate that SP-D and SP-A might provide an important link between innate and adaptive immunity, by modulation of both DC and T cell functions. Borron P, Veldhuizen RA, Lewis JF, Possmayer F, Caveney A, Inchley K, McFadden RG, Fraher LJ. Surfactant associated protein-A inhibits human lymphocyte proliferation and IL-2 production. Am J Respir Cell Mol Biol. 1996 Jul; 15 (1): 115-21. Borron P, McCormack FX, Elhalwagi BM, Chroneos ZC, Lewis JF, Zhu S, Wright JR, Shepherd VL, Possmayer F, Inchley K, Fraher LJ. Surfactant protein A inhibits T cell proliferation via its collagen-like tail and a 210-kDa receptor. Am J Physiol. 1998 Oct; 275 (4 Pt 1): L679-86. Borron PJ, Crouch EC, Lewis JF, Wright JR, Possmayer F, Fraher LJ. Recombinant rat surfactant-associated protein D inhibits human T lymphocyte proliferation and IL-2 production. J Immunol. 1998 Nov 1; 161 (9): 4599-603. Borron PJ, Mostaghel EA, Doyle C, Walsh ES, McHeyzer-Williams MG, Wright JR. Pulmonary surfactant proteins A and D directly suppress CD3+/CD4+ cell function: evidence for two shared mechanisms. J Immunol. 2002 Nov 15; 169 (10): 5844-50. Brinker KG, Martin E, Borron P, Mostaghel E, Doyle C, Harding CV, Wright JR. Surfactant protein D enhances bacterial antigen presentation by bone marrow-derived dendritic cells. Am J Physiol Lung Cell Mol Physiol. 2001 Dec; 281 (6): L1453-63. Brinker KG, Garner H, Wright JR. Surfactant protein A modulates the differentiation of murine bone marrow-derived dendritic cells. Am J Physiol Lung Cell Mol Physiol. 2003 Jan; 284 (1): L232-41. Epub 2002 Sep 13. Fadok VA, Bratton DL, Konowal A, Freed PW, Westcott JY, Henson PM. Macrophages that have ingested apoptotic cells in vitro inhibit proinflammatory cytokine production through autocrine/paracrine mechanisms involving TGF-beta, PGE2, and PAF. J Clin Invest. 1998 Feb 15; 101 (4): 890-8. Palaniyar N, Clark H, Nadesalingam J, Hawgood S, Reid KB. Surfactant protein D binds genomic DNA and apoptotic cells, and enhances their clearance, in vivo. Ann N Y Acad Sci. 2003 Dec; 1010: 471-5. Palaniyar N, Nadesalingam J, Clark H, Shih MJ, Dodds AW, Reid KB. Nucleic acid is a novel ligand for innate, immune pattern recognition collectins surfactant proteins A and D and mannose-binding lectin. J Biol Chem. 2004 Jul 30; 279 (31): 32728-36. Epub 2004 May 15. Reidy MF, Wright JR. Surfactant protein A enhances apoptotic cell uptake and TGF-beta1 release by inflammatory alveolar macrophages. Am J Physiol Lung Cell Mol Physiol. 2003 Oct; 285 (4): L854-61. Epub 2003 Jun 6. |
SP-A and SP-D, as well as MBL, bind DNA from a variety of origins, including mice and bacteria82. Binding occurs through both the CRDs and the collagen-like regions. SP-D effectively binds and aggregates alveolarmacrophage DNA83, and it enhances the uptake of DNA by human monocytic cells84. Binding of the collectins to cell-surface DNA might be one mechanism by which they mediate enhanced phagocytosis of apoptotic cells.
A consequence of apoptotic-body uptake by a phagocyte is induction of an anti-inflammatory response by the phagocyte. For example, macrophage uptake of apoptotic cells results in release of antiinflammatory mediators, such as transforming growth factor-β (TGF-β), IL-10 and prostaglandin E2 (REF. 85)[sic]. This response is in contrast to the release of proinflammatory cytokines that occurs when phagocytes ingest a microorganism. In addition to enhancing the uptake of apoptotic cells, SP-A also enhanced the release of TGF-β by macrophages86, indicating that SP-A can promote resolution of inflammation at several levels of the apoptotic-cell clearance process. Surfactant links innate and adaptive immunity Recent studies have provided support for the concept that surfactant might have a role in linking innate and adaptive immunity in the lung by modulating functions of both DCs and T cells. [...] Recent studies have shown that SP-A and SP-D have different effects on DC functions. For example, SP-D enhances the uptake and presentation of a model antigen expressed by Escherichia coli95. SP-A, but not SP-D, inhibits maturation of DCs, as assessed by cell-surface marker expression, and functional activity, such as phagocytosis and chemotaxis96. [...] Subsequent studies by Borron and colleagues99,100 showed that SP-A and SP-D inhibit proliferation of T cells that have been stimulated with plant lectins, CD3-specific antibodies or phorbol esters, by a process that is thought to be mediated (at least, in part) by inhibition of IL-2 production. In addition, both the collagen-like region46 and the CRD101 of SP-A have been implicated in the inhibition of lymphocyte function, probably owing to inhibition of calcium signalling102. [...] As noted by Shepherd55 in an invited commentary, these studies indicate that SP-D and SP-A might provide an important link between innate and adaptive immunity, by modulation of DC and T-cell functions (FIG. 5). 46. Borron, P. et al. Surfactant protein A inhibits T cell proliferation via its collagen-like tail and a 210-kDa receptor. Am. J. Physiol. Lung Cell. Mol. Physiol. 275, L679–L686 (1998). 82. Palaniyar, N. et al. Nucleic acid is a novel ligand for innate immune pattern recognition collectins surfactant proteins A and D and mannose-binding lectin. J. Biol. Chem. 279, 32728–32736 (2004). 83. Palaniyar, N., Clark, H., Nadesalingam, J., Hawgood, S. & Reid, K. B. Surfactant protein D binds genomic DNA and apoptotic cells, and enhances their clearance, in vivo. Ann. NY Acad. Sci. 1010, 471–475 (2003). 84. Palaniyar, N., Nadesalingam, J. & Reid, K. B. Innate immune collectins bind nucleic acids and enhance DNA clearance in vitro. Ann. NY Acad. Sci. 1010, 467–470 (2003). 85. Fadok, V. A. et al. Macrophages that have ingested apoptotic cells in vitro inhibit proinflammatory cytokine production through autocrine/paracrine mechanisms involving TGF-β, PGE2, and PAF. J. Clin. Invest. 101, 890–898 (1998). 86. Reidy, M. F. & Wright, J. R. Surfactant protein A enhances apoptotic cell uptake and TGF-β1 release by inflammatory alveolar macrophages. Am. J. Physiol. Lung Cell Mol. Physiol. 285, L854–L861 (2003). 95. Brinker, K. G. et al. Surfactant protein D enhances bacterial antigen presentation by bone marrow-derived dendritic cells. Am. J. Physiol. Lung Cell. Mol. Physiol. 281, L1453– L1463 (2001). 96. Brinker, K. G., Garner, H. & Wright, J. R. Surfactant protein A modulates the differentiation of murine bone marrow-derived dendritic cells. Am. J. Physiol. Lung Cell. Mol. Physiol. 284, L232–L241 (2003). 99. Borron, P. et al. Surfactant associated protein-A inhibits human lymphocyte proliferation and IL-2 production. Am. J. Respir. Cell Mol. Biol. 15, 115–121 (1996). 100. Borron, P. J. et al. Recombinant rat surfactant-associated protein D inhibits human T lymphocyte proliferation and IL-2 production. J. Immunol. 161, 4599–4603 (1998). 101. Wang, J. Y., Shieh, C. C., You, P. F., Lei, H. Y. & Reid, K. B. Inhibitory effect of pulmonary surfactant proteins A and D on allergen-induced lymphocyte proliferation and histamine release in children with asthma. Am. J. Respir. Crit. Care Med. 158, 510–518 (1998). 102. Borron, P. J. et al. Pulmonary surfactant proteins A and D directly suppress CD3+/CD4+ cell function: evidence for two shared mechanisms. J. Immunol. 169, 5844–5850 (2002). |
The source is not given here. Continuation of Fragment_020_08. Note: there are two publications "Borron et al. 1998" listed in the bibliography. |
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Letzte Bearbeitung dieser Seite: durch Benutzer:Graf Isolan, Zeitstempel: 20140310121138