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Crosstalk between autoreactive T cells and alveolar type II epithelial cells in inflammation and tolerance

von Dr. Marcus Gereke

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[1.] Mag/Fragment 018 01 - Diskussion
Zuletzt bearbeitet: 2014-03-10 13:25:58 Hindemith
Fehrenbach 2001, Fragment, Gesichtet, Mag, SMWFragment, Schutzlevel sysop, Verschleierung

Typus
Verschleierung
Bearbeiter
Hindemith
Gesichtet
Yes
Untersuchte Arbeit:
Seite: 18, Zeilen: 1-8
Quelle: Fehrenbach 2001
Seite(n): 35, Zeilen: 35: r.col: last paragraph; 38: r.col: 22-26, 41-43
[Although the bronchiolar Clara cells and submucosal cells also synthesize and release the mature proteins SP-A, SP-B and SP-D (Kalina et al., 1992; Voorhout et al., 1992) the alveolar type II epithelial cell is the only type of pulmonary cell that] produces all surfactant components including phospholipids as well as all four surfactant proteins. The mature 3.5-3.7 kDa small SP-C is thought to be exclusively released by AECII cells (Beers et al., 1994; Phelps and Floros et al., 1991).

About 85% of the secreted surfactant is taken up again, metabolised and re-secreted by AECII. Re-uptake and recycling have been demonstrated for all surfactant lipids and for all four surfactant proteins. The degradation of surfactant is accomplished by alveolar macrophages with only minimal contribution (Herbein et al., 2000; Nicholas, 1996; Young et al., 1993).


Beers MF, Kim CY, Dodia C, Fisher AB. Localization, synthesis, and processing of surfactant protein SP-C in rat lung analyzed by epitope-specific antipeptide antibodies. J Biol Chem. 1994 Aug 12; 269 (32): 20318-28.

Herbein JF, Savov J, Wright JR. Binding and uptake of surfactant protein D by freshly isolated rat alveolar type II cells. Am J Physiol Lung Cell Mol Physiol. 2000 Apr; 278 (4): L830-9.

Kalina M, Mason RJ, Shannon JM. Surfactant protein C is expressed in alveolar type II cells but not in Clara cells of rat lung. Am J Respir Cell Mol Biol. 1992 Jun; 6 (6): 594-600.

Nicholas TE. Pulmonary surfactant: no mere paint on the alveolar wall. Respirology. 1996 Dec; 1 (4): 247-57. Review.

Phelps DS, Floros J. Localization of pulmonary surfactant proteins using immunohistochemistry and tissue in situ hybridization. Exp Lung Res. 1991 Nov-Dec; 17 (6): 985-95.

Voorhout WF, Veenendaal T, Kuroki Y, Ogasawara Y, van Golde LM, Geuze HJ. Immunocytochemical localization of surfactant protein D (SP-D) in type II cells, Clara cells, and alveolar macrophages of rat lung. J Histochem Cytochem. 1992 Oct; 40 (10): 1589-97.

Young SL, Fram EK, Larson E, Wright JR. Recycling of surfactant lipid and apoprotein-A studied by electron microscopic autoradiography. Am J Physiol. 1993 Jul; 265 (1Pt1): L19-26.

[page 35]

Synthesis

Although the bronchiolar Clara cells synthesise and release the mature proteins SP-A, SP-B, and SP-D (Fig. 2a) [37,38], the AE2 cell is the only type of pulmonary cell that produces all the surfactant components (phospholipids [Fig. 3] as well as all four surfactant proteins). The mature 3.5-3.7 kDa small SP-C (Fig. 2b) is thought to be released by AE2 cells only [39,40].

[page 38]

Today it is established that most of the secreted surfactant — estimated at about 85% [24] — is taken up again, metabolised and re-secreted by the AE2 cells. Re-uptake and recycling have been demonstrated for surfactant lipids [58] and all four surfactant proteins [51,58,96,97]. [...]

The degradation of surfactant is accomplished by the alveolar macrophages with only minimal contribution, if any, from AE2 cells.


24. Nicholas TE: Pulmonary surfactant: no mere paint on the alveolar wall. Respirology 1996, 1:247–257.

37. Kalina M, Mason RJ, Shannon JM: Surfactant protein C is expressed in alveolar type II cells but not in Clara cells of rat lung. Am J Respir Cell Mol Biol 1992, 6:594–600.

38. Voorhout WF, Veenendaal T, Kuroki Y, Ogasawara Y, van Golde LM, Geuze HJ: Immunocytochemical localization of surfactant protein D (SP-D) in type II cells, Clara cells, and alveolar macrophages of rat lung. J Histochem Cytochem 1992, 40: 1589–1597.

39. Phelps DS, Floros J: Localization of pulmonary surfactant proteins using immunohistochemistry and tissue in situ hybridization. Exp Lung Res 1991, 17:985–995.

40. Beers MF, Kim CY, Dodia C, Fisher AB: Localization, synthesis, and processing of surfactant protein SP-C in rat lung analyzed by epitope-specific antipeptide antibodies. J Biol Chem 1994, 269:20318–20328.

51. Herbein JF, Savov J, Wright JR: Binding and uptake of surfactant protein D by freshly isolated rat alveolar type II cells. Am J Physiol 2000, 278:L830–839.

58. Young SL, Fram EK, Larson E, Wright JR: Recycling of surfactant lipid and apoprotein-A studied by electron microscopic autoradiography. Am J Physiol 1993, 265:L19–L26.

96. Breslin JS, Weaver TE: Binding, uptake, and localization of surfactant protein B in isolated rat alveolar type II cells. Am J Physiol 1992, 262:L699–707.

97. Pinto RA, Wright JR, Lesikar D, Benson BJ, Clements JA: Uptake of pulmonary surfactant protein C into adult rat lung lamellar bodies. J Appl Physiol 1993, 74:1005–1011.

Anmerkungen

The source is mentioned further up on the previous page, but without any indication that the here documented passage might have been taken from it. See Mag/Fragment_017_18.

Sichter
(Hindemith) Schumann


[2.] Mag/Fragment 018 09 - Diskussion
Zuletzt bearbeitet: 2014-03-10 13:25:22 Hindemith
Fragment, Gesichtet, Mag, SMWFragment, Schutzlevel sysop, Verschleierung, Wright 2005

Typus
Verschleierung
Bearbeiter
PlagProf:-)
Gesichtet
Yes
Untersuchte Arbeit:
Seite: 18, Zeilen: 9-27
Quelle: Wright_2005
Seite(n): 58-59, Zeilen: S. 58: 2. Spalte, 26-28, S. 59: 2. Spalte, 22 ff.
2.3.1 Immunoregulatory functions of surfactant proteins

As mentioned above, the host defence functions of surfactant are primarily mediated by SP-A and SP-D, which are members of the collectin family of proteins. SP-A and SP-D have been also localized to non-pulmonary sites, including the trachea, brain, testes, salivary glands, lachrymal glands, heart, prostate, kidney, pancreas and the female urogenital tract (Leth-Larsen et al., 2004; Lin et al., 2000; Madsen et al., 2000; Rubio et al., 1995), although it is not yet clear whether all of these organs express sufficient amounts of protein for it to be physiologically effective.

Among their well-established role as opsonins, SP-A and SP-D also have functions in initiating parturition, facilitating clearance of apoptotic cells and directly killing bacteria.

2.3.2 Collectin structure

In addition to the two lung collectins SP-A and SP-D, serum collectins have been identified in humans (mannose-binding lectin, MBL) and in bovidae (conglutinin, CL-43 and CL-46) (Hansen and Holmskov, 2002).

SP-A and SP-D are synthesized as primary translation products of approximately 26-36kDa and 43kDa, respectively (figure 3). The collagen-like domain is N-terminal to a coiled-coil structure that precedes the C-terminal lectin domain. The lectin domains mediate the interaction of collectins with a wide varity of pathogens. The collagen domains vary greatly in length (Holmskov et al., 2003).

The host-defence functions of surfactant are primarily mediated by SP-A and SP-D, which are members of the collectin family of proteins.

[P. 59] [...]

SP-A and SP-D have been localized to non-pulmonary sites, including the trachea, brain, testes, salivary glands, lachrymal glands, heart, prostate, kidney, pancreas and the female urogenital tract11–14, although it is not yet clear whether all of these organs express sufficient amounts of protein for it to be physiologically effective. [...] An emphasis is placed on recent studies showing that, in addition to their well-established role as opsonins, SP-A and SP-D also have novel functions in initiating parturition, facilitating clearance of apoptotic cells and directly killing bacteria.

Collectin structure

In addition to the two lung collectins SP-A and SP-D (FIG. 2), serum collectins have been identified in humans (mannose-binding lectin,MBL) and in bovidae (conglutinin, CL-43 and CL-46)15. [...] SP-A and SP-D are synthesized as primary translation products of approximately 26–36 kDa and 43 kDa, respectively. The collagen-like domain is N-terminal to a coiled-coil structure that precedes the lectin domain. The collagen domains vary greatly in length, ranging from 19 Gly-X-Y triplets in MBL to 59 in human SP-D18. --- 11. Rubio, S. et al. Pulmonary surfactant protein A (SP-A) is expressed by epithelial cells of small and large intestine. J. Biol. Chem. 270, 12162–12169 (1995).

12. Lin, Z. et al. Both human SP-A1 and SP–A2 genes are expressed in small and large intestine. Am. J. Respir. Crit. Care Med. 161, A43 (2000).

13. Madsen, J. et al. Localization of lung surfactant protein D on mucosal surfaces in human tissue. J. Immunol. 164, 5866–5870 (2000).

14. Leth-Larsen, R., Floridon, C., Nielsen, O. & Holmskov, U. Surfactant protein D in the female genital tract. Mol. Hum. Reprod. 10, 149–154 (2004).

15. Hansen, S. & Holmskov, U. Lung surfactant protein D (SP-D) and the molecular diverted descendants: conglutinin, CL-43 and CL-46. Immunobiology 205, 498–517 (2002).

18. Holmskov, U., Thiel, S. & Jensenius, J. C. Collectins and ficolins: humoral lectins of the innate immune defense. Annu. Rev. Immunol. 21, 547–578 (2003).

Anmerkungen

The source is not indicated. The references are identical. Heading 2.3.1 is identical with the title of Wright 2005.

Sichter
(SleepyHollow02)



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