| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
Biofilms consist of 10-25% bacterial cells and 75-90% exopolysaccharide (EPS), and have been increasingly recognized as being important in human infectious diseases. We have purified an exopolysaccharide from a clinical isolate of Prevotella nigrescens and found that this EPS acted as an anti-phagocytotic factor and crucial forinducing abscess formation in mice. Chemical analysis showed that isolated EPS mainly consisted of mannose, and methylation analysis of EPS indicated that the linkages of mannose were primarily (1-2, 1-6), (1-2), (1-6), and (1-3). In this study, we investigated the effects of the EPS on human endothelial cells in terms of the cytokine and chemokine production. This EPS did not enhance the inflammatory cytokine production of endothelial cells or peripheral blood mononuclear cells, however, this EPS slightly inhibited a stimulation of LPS on these cells.
To better understand the relation between commensal bacteria and mucosa-associated immune responses, the lymphocyte redistribution was also examined in germ free rats exposed to a conventional pathogen-free microflora. Without commensal bacterial flora, B cells in the mucosa-associated lymphoid follicles did not express Bcl-2 through the experimental period (5 months). The cellular redistribution patterns and phenotypic characteristics observed after colonization suggested that immature dendritic cells (DCs), but not B cells, are involved in antigen presentation during primary immune responses against intestinal bacteria.
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