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Gingipains in the culture supernatant of Porphyromonas gingivalis cleave CD4 and CD8 on human T cells (2002)

Kitamura, Y. ; Yoneda, M. ; Imamura, T. ; [et al.]

Oxford, UK : Munksgaard International Publishers

Journal of periodontal research 37 (2002), S. 0

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ISSN: 1600-0765

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Medicine

Notes: Porphyromonas gingivalis has been shown to attack host defense systems through proteolytic cleavage of a wide variety of members of the systems. In this study, we examined the ability of P. gingivalis culture supernatant to alter the expression of human T cell surface proteins. As judged by flow cytometric analysis, detection of CD4 expression was completely eliminated by the supernatant, but CD8 was less sensitive. When the culture supernatant was added with reducing agents, proteolytic activity was enhanced, resulting in the cleavage of CD8. Mitogenic response of T cells to phytohemagglutinin or concanavalin A was decreased by the treatment of the cells with the culture supernatant of P. gingivalis. The three forms of gingipains (high molecular mass arginine-specific gingipain, arginine-specific gingipain 2 and lysine-specific gingipain) purified from the culture supernatant of P. gingivalis actively cleaved CD4 and CD8 on human T cells, indicating that proteolytic activity of the culture supernatant was due to gingipains. These results suggest that cysteine proteinases like gingipains released from P. gingivalis cleave T cell surface proteins and impede T cell function.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1034/j.1600-0765.2002.01364.x

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Development of Mineralized Nodules in Fetal Rat Mandibular Osteogenic Precursor Cells: Requirement for Dexamethasone but Not for β-Glycerophosphate (2000)

Abe, Y. ; Aida, Y. ; Abe, T. ; [et al.]

Springer

Calcified tissue international 66 (2000), S. 66-69

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ISSN: 1432-0827

Keywords: Key words: Alkaline phosphatase —β-Glycerophosphate—Dexamethasone—Mineralization—Osteoprogenitor cell.

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract: We have reported that a cell population obtained from fetal rat mandible with neutral protease (Pro I) has a unique differentiation sequence in which the elevation of alkaline phosphatase (ALPase), calcium accumulation, and collagen synthesis occurs simultaneously. In this report, we further characterized Pro I-released population of cells by studying the effect of dexamethasone (Dex) or β-glycerophosphate (β-GP) on the formation of bone nodules. The formation of bone nodules in Pro I-released population of cells (ProIRPC) was augmented by the addition of Dex (10−7 M) from days 3 to 14, suggesting that Pro IRPC contained osteoprogenitor (OP) cells. A 24-hour pulse treatment of ProIRPC released population of cells with Dex on days 9 and 12 resulted in an increase in the number of nodules but treatment on days 3, 6, or 15 did not. The number of bone nodules formed in Pro IRPC pulse treated with Dex on day 9 was comparable with that in Pro IRPC treated with Dex from days 3 to 14. Dex caused an earlier elevation of ALPase, in which maximal expression was observed on day 10. β-GP caused a prolonged elevation of ALPase, but did not affect the formation of bone nodules. Unlike Pro I-released population of cells, rat calvarial cells did not form mineralized nodules without β-GP, and showed that a Dex-responsive period on bone nodule formation in rat calvarial cells was at preconfluency (days 0 and 1). Thus, it appeared that the Dex-induced differentiation of early OP cells in Pro IRPCs occurred during the limited period from day 9 to day 12. Pro IRPC was found to have an unique characteristic that bone nodule formation was not affected by β-GP.