| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
In this study using the Iipopolysaccharides (LPS) from Porphyronwnas gingivalis as well as other periodontopathic bacteria including Prevotella intermedia, Actinobacillus actinomycetemcomitans and Eikenella corrodens (PgLPS, AaLPS, PiLPS and EiLPS, respectively), the nature of LPS-induced signal transduction mechanism that mediates later cellular responses of Blymphocytes was examined. When detected under Western blot analysis by using the monoclonal anti-phosphotyrosine antibody, all the LPSs as well as Escherichia coli LPS (EcLPS) induced tyrosine phosphorylation in the B lymphocytes from LPS-responsive C3H/HeN mice. In the LPS-hyporesponsive C3H/HeJ B lymphocytes, however, the trigger signals could be induced by PgLPS and PiLPS, but not by AaLPS or EiLPS.Furtherrnore, lipid A from Salmonella minnesota also induced tyrosine phosphorylation in C3H/HeN B lymphocytes. It was reported that the lipid A moieties of PgLPS and PiLPS were quite different from those of EcLPS, AaLPS or EiLPS.Th
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us, these results si.iggest that lipid A moiety of LPS could be potent for the LPS-induced tyrosine phosphoxylation in B lymphocytes. The treatment with tyrosine kinase inhibitors, herbimycin A and Lenistein, abrogated the LPS-induced tyrosine phosphorylation and the proliferative response, suggesting that LPS-induced tyrosine phosphorylation could be an important signaling event that might lead to cellular responses. However, no obvious effect has been observed by the treatment with a phosphatase inhibitor (phenylarsine oxide). In addition, increased serine threonine protein phosphorylation in B lymphocytes could be also important, since the proliferative response following LPS stimulation was inhibited by the preincubation with a serine threonine kinase inhibitor, staurosponne. Taken together, the present findings suggest that the pen odontopathic bacteria have a potent property to induce the stimulation of B lymphocytes by the lipid A moiety, in which increased tyrosine phosphorylation folJowed by other protein phosphorylations could be important signaling events that might lead to cellular responses. Less
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