Development of inflammation and augmented chemotactic responsiveness of murine peritoneal macrophages following treatment with Entamoeba histolytica trophozoites.

The accumulation of inflammatory cells in the peritoneal cavity of C57BL/6 mice was examined following intraperitoneal injection of Entamoeba histolytica trophozoites. Two different strains of E. histolytica were used: a virulent strain (IP:0682:1) and a non-virulent strain (DKB). Injection of 10(6) trophozoites of either strain resulted in significant increases in the numbers of total peritoneal cells, macrophages and polymorphonuclear cells as compared to either saline-injected control mice or mice injected with 10-fold lower doses of trophozoites. The in vitro chemotactic response of macrophages from amoebae-induced exudates was also examined. Macrophages from mice treated with strain IP:0682:1 or DKB strain trophozoites were more responsive to complement-derived chemotactic factors than macrophages from saline-injected mice. This increase was significant on day 2 and persisted at enhanced levels until day 20 when the experiment was terminated. In addition, it was found that trophozoites activated normal mouse serum resulting in the production of serum-derived chemotactic activity.