| 1. |
- Björnberg, F, et al.
(författare)
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Metalloproteases and serineproteases are involved in the cleavage of the two tumour necrosis factor (TNF) receptors to soluble forms in the myeloid cell lines U-937 and THP-1
- 1995
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Ingår i: Scandinavian Journal of Immunology. - 0300-9475. ; 42:4, s. 24-418
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Tidskriftsartikel (refereegranskat)abstract
- The proteolytic processing of the two TNF receptors (TNF-R55 and TNF-R75) into soluble forms was investigated in the myeloid cell lines U-937 and THP-1. Phorbol myristate acetate (PMA) rapidly stimulated release of soluble forms of both TNF-receptors. Incubations were made with PMA and protease inhibitors directed against different target protease groups. The serineprotease inhibitors TPCK and dichloroisocoumarin and the metalloprotease inhibitor 1,10-phenanthroline reduced PMA-induced release of both soluble receptor forms with about 60-70%. Furthermore, 1,10-phenanthroline also reduced PMA-induced down-regulation of TNF-receptors in both cell lines as judged by TNF-binding to cells. Reduced down-regulation and TNF-receptor shedding by 1,10-phenanthroline was reversed by Zn2+, indicating involvement of a Zn(2+)-dependent metalloprotease. Thus, both serine proteases and metalloproteases are involved in the processing of TNF-receptors.
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| 2. |
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| 3. |
- Bremer, B, et al.
(författare)
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More characters or more taxa for a robust phylogeny - Case study from the coffee family (Rubiaceae)
- 1999
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Ingår i: SYSTEMATIC BIOLOGY. - : TAYLOR & FRANCIS LTD. - 1063-5157. ; 48:3, s. 413-435
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Tidskriftsartikel (refereegranskat)abstract
- Using different data sets mainly from the plant family Rubiaceae, but in parts also from the Apocynaceae, Asteraceae, Lardizabalaceae, Saxifragaceae, and Solanaceae, we have investigated the effect of number of characters, number of taxa, and kind of
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| 4. |
- Richter, J, et al.
(författare)
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TNF-induced superoxide anion production in adherent human neutrophils involves both the p55 and p75 TNF receptor
- 1995
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Ingår i: Journal of Immunology. - 0022-1767. ; 154:8, s. 9-4142
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Tidskriftsartikel (refereegranskat)abstract
- TNF, a potent activator of neutrophil granulocytes, acts via two cell-surface receptors: the p55-TNF receptor (TNF-R55) and the p75-TNF receptor (TNF-R75), which can be cleaved from the cell surface and thus form soluble TNF-binding proteins (TNF-BP). The role of the two receptors in activation of the neutrophil respiratory burst was investigated. Two mAbs reacting with TNF-R55 (H398 and TBP2) induced O2 release in a similar manner but to a lesser extent than TNF. TBP2, however, required preincubation at 4 degrees C to exert its effect. Preincubation of neutrophils (both at 4 and 37 degrees C) with mAb to TNF-R75 decreased TNF-induced superoxide anion production by 67 and 64%, respectively, indicating the essential role also for TNF-R75 in neutrophil activation. This inhibitory effect could not be explained by cross-down-regulation of TNF-R55 because the TNF-R75 mAb had no effect on TNF binding to TNF-R55 as determined by binding of 125I-labeled TNF or release of TNF-R55-BP as measured by ELISA. Furthermore, the TNF-R75 mAb did not decrease superoxide anion generation induced by the TNF-R55 mAb H398, thus ruling out that the inhibitory effect of the TNF-R75 mAb is due to inhibition of the signaling pathway downstream of TNF-R55. In contrast to the TNF-R75 mAb, TNF-R55 mAbs induced down-regulation of TNF-R75 and shedding of both TNF-R55-BP and TNF-R75-BP. We conclude that both TNF-R55 and TNF-R75 are involved in TNF-induced activation of the neutrophil respiratory burst.
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| 5. |
- Rydberg, Johan, et al.
(författare)
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Assessment of a possible imbalance between tumor necrosis factor (TNF) and soluble TNF receptor forms in tuberculous infection of the central nervous system
- 1995
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Ingår i: Journal of Infectious Diseases. - 1537-6613. ; 172:1, s. 301-304
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Tidskriftsartikel (refereegranskat)abstract
- Distributions of tumor necrosis factor (TNF) and its soluble receptor forms, R55-BP and R75-BP, were analyzed in the cerebrospinal fluid of patients with severe acute or chronic central nervous system infections. Tuberculous infections were associated with high ratios of R55-BP and R75-BP to TNF, 27.2 and 28.0, respectively, suggesting a small biologically active fraction of TNF. The opposite was found in subjects with acute bacterial meningitis. They had large fractions of biologically active TNF and thus low ratios of R55-BP and R75-BP to TNF, 3.7 and 4.0, respectively. It is hypothesized that chronic infectious diseases, such as tuberculous infections, may be associated with inadequate production of TNF and a concomitant relative increase of soluble TNF receptors, which may prolong the disease.
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