Effects of interleukin-8 and Helicobacter pylori on histamine release from isolated canine gastric mucosal mast cells

Background. In recent studies, the involvement of mast cells in the pathogenesis of Helicobacter pylori infection was suggested. In the present study, using isolated canine gastric mucosal mast cells, we undertook to elucidate the effects of interleukin-8 (IL-8) and H. pylori on histamine release from these cells. Methods. Enriched canine gastric mucosal mast cells (50% target cells) were incubated in Hanks medium with IL-8, or water extract or sonicate of H. pylori for 15 min at 37°C. The content of histamine in the supernatants and the cell pellets after centrifugation was assayed with a histamine radioimmunoassay (RIA) kit. Results. IL-8 (50 ng/ml) and concanavalin A (20 μg/ml) significantly increased histamine release from enriched gastric mucosal mast cells. Dose-dependent stimulation of histamine release by IL-8 (5–50 ng/ml) was also seen. Water extract and sonicate of H. pylori (10⁸ bacteria) increased histamine release from mast cells. A concentration-dependent stimulation of histamine release by water extract or sonicate was also seen. The maximal response of histamine release was seen at the highest concentration of the water extract or sonicate. Conclusions. The results indicated that IL-8 and H. pylori had stimulatory effects on histamine release from canine gastric mucosal mast cells. The results imply that IL-8 and soluble factors of H. pylori may accelerate inflammation of the gastric mucosa via histamine release from mast cells. Received: February 28, 2001 / Accepted: July 6, 2001