Killing of Escherichia coli by Mononuclear Phagocytes and Neutrophils Stimulated In Vitro with β-1, 3-D-Polyglucose Derivatives

抄録

Human monocytes, human peritoneal macrophages, mouse peritoneal macrophages and human peripheral neutrophils pretreated with β-1, 3-D-polyglucose derivatives showed pronounced bactericidal capacity to Escherichia coli compared to control cells. The increased bactericidal capacity was detectable in mononuclear phagocytes over a wide range of concentrations of bacteria. Granulocytes, however, showed bactericidal capacity only at low concentrations of bacteria. The pretreated mononuclear phagocytes released significant amounts of IL-1 and PGE₂. However, there was no significant release of tumor necrosis factor (TNF). By incubating unstimulated cells with purified IL-1 and TNF, the bactericidal activity of neutrophils and mononuclear phagocytes was enhanced. Our data indicate that the inability of neutrophils stimulated with β-1, 3-D-polyglucose derivatives to kill large numbers of bacteria could be overcome by a combined treatment with purified IL-1 or TNF in addition to β-1, 3-D-polyglucose derivatives. By incubating unstimulated cells with medium from β-1, 3-D-polyglucose-treated human peritoneal macrophages, the bactericidal activity of the cells was enhanced to the same extent as cells pretreated with purified TNF and IL-1. Cells incubated with IL-1-depleted medium from β-1, 3-D-polyglucose-treated human peritoneal macrophages, showed reduced bactericidal activity compared to cells incubated with undepleted medium. These studies demonstrate that β-1, 3-D-polyglucose-treated mononuclear phagocytes and neutrophils show enhanced bactericidal activity. The enhanced activity is partly caused by stimulation of the cells with IL-1 released from mononuclear phagocytes and partly by other unknown effects of β-1, 3-D-polyglucose derivatives on both mononuclear phagocytes and neutrophils.