| Project/Area Number |
05454192
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Osaka University |
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Principal Investigator |
HAMADA Shigeyuki Osaka University Faculty of Dentistry, Prof., 歯学部, 教授 (60028777)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Ichiro Osaka University Faculty of Dentistry, Ass.Prof., 歯学部, 助手 (20206791)
KIMURA Shigenobu Osaka University Faculty of Dentistry, Ass.Prof., 歯学部, 講師 (10177917)
森崎 市治郎 大阪大学, 歯学部・附属病院, 助教授 (30116115)
藤原 卓 大阪大学, 歯学部・附属病院, 講師 (00228975)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1995: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Endotoxin (lipopolysaccharide) / Periodontopathic bacteria / Host responses / murine B lymphocytes / Tyrosine Protein Phosphorylation / Porphyromonas gingivalis / fimbriae / Porphyromomas gingivalis / 歯周病原菌 / 内毒素 / LPS / 表面抗原 / マウス / 線維芽細胞 / C3H / HeJマウス / シグナル伝達 / 歯周炎 |
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| Research Abstract |
Selected species of Gram-negative anaerobes including Porphyromonas gingivalis have been implicated in the pathogenesis of periodontal diseases. We have shown that P.gingivalis lipopolysaccharide (PgLPS) are composed of unique constituents and exhibit characteristic immunobiological activities. Splenic B lymphocytes from C3H/HeJ mice known to be hyporesponsive to Escherichia coli LPS (EcLPS) did proliferate after exposure to PgLPS.Since periodontitis lesions are characterized as infiltration with increased numbers of B lymphocytes/plasma cells, it is important to elucidate the mechanisms of stimulation with LPS,especially the mechanisms of signal transduction in terms of B cell activation upon stimulation with LPS.However, the intracellular signals generated by LPS have not yet been well defined.
In the present study, we first examined the molecular effect of PgLPS on the tyrosineprotein phosphorylation in the splenic B lymphocytes from LPS-responsive C3H/HeN and LPS-hyporesponsive C3H/HeJ mice. The results indicated that PgLPS induced tyrosine phosphorylation of selected membrane proteins that included the phosphoproteins with apparent molecular masses of 24.8kDa and 26.0kDa (p24.8 and p26.0) in the B lymphocytes from both strains of mice, while EcLPS induced p24.8 and p26.0 in C3H/HeN B lymphocytes only. These findings suggest that through the same tyrosine phosphorylation pathway as observed in C3H/HeN B lymphocytes, PgLPS induced the activation of C3H/HeJ B lymphocytes in which a trigger signal by EcLPS could not be transduced to initiate tyrosine protein phosphorylation.
Second, we examined immunochemical specificity of LPS and the molecular property of the gene encoding the fimbrilin of P.gingivalis strains. The seults showed that the molecular structure of the fimbrilin genes was not homologous, suggesting that molecular modifications in the fimbrilin gene should occur during in vitro passages and maintenance of strains of P.gingivalis.
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