| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Research Abstract |
Neutrophils play an important role in intestinal inflammation by interacting with intestinal epithelial cells. In this study, we evaluated neutrophil adhesion to intestinal epithelial cells using intestinal epithelial cell line HT29 stimulated with tumor necrosis factor a (TNF-α) and histamine.
(1) The TNF-α and histamine stimulation markedly increased neutrophil adhesion. The increased adhesion was inhibited by anti-CD11b and anti-CD18 antibodies, but not by anti-CD11a and anti-CD54 (ICAM- 1) antibodies.
(2) Interestingly, flow cytometric analysis revealed that ICAM-1 expression on HT29 cells was not changed by TNF-αand histamine stimulation. These observations indicate that exposure of HT29 cells to TNF-αand histamine induces CD11b/CD18 (Mac-1)-dependent but CD11a/CD18 (LFA-1)-independent neutrophil adhesion to intestinal epithelial cells, and ICAM-1 is not likely involved in the interactions.
(3) Moreover, the increased adhesion was inhibited by proteinase K treatment but not cyclohexi
… More
mide treatment of HT29 cells, suggesting that epithelial cell ligand(s) for neutrophils is likely protein molecule(s) that is exposed on the cell by stimulation independent of protein synthesis.
(4) Even when HT29 cells were treated with endoglycosidase H, sialidase or tunicamycin, neutrophil adhesion to TNF-α- or histamine-stimulated HT29 cells was not affected, suggesting that sugar chains may noy be involved in CD11b/CD18-mediated neutrophil adhesion to HT29 cells.
(5) Treatment of HT29 cells with phosphatidylinositol-specific phospholipase C which cleaves glycosylphosphatidyl inositol (GPI)-anchored protein, did not affect neutrophil adhesion to TNF-α- or histamine-stimulated HT29 cells. In addition, neither RGD peptide nor heparinase treatment of HT29 cells affected neutrophil adhesion to stimulated HT29 cells. These results suggest that GPI-anchored protein, heparin-like glycosaminoglycans and extracellular matrix protein containing RGD sequences are unlikely involved in neutrophil-HT29 cell interactions. Less
|
