Manganese chloride enhances natural cell-mediated immune effector cell function: effects on macrophages

A single intramuscular injection of MnC12 in mice caused an increase in macrophage functional activity. Spleen cell antibody-dependent cell-mediated cytotoxicity against both chicken erythrocytes and P815 tumor cell targets was enhanced 24 h following a single injection of MnC12. Enhanced antibody-dependent cell-mediated cytotoxicity activity following MnC12 treatment was not associated with a change in spleen cellularities compared with saline-injected mice. Resident peritoneal macrophages from mice injected intramuscularly with MnC12 displayed enhanced phagocytic activity for chicken erythrocytes in the presence or absence of opsonizing antibody. Enhanced cytolytic activity against P815 mastocytoma target cells and enhanced cytostatic activity against MBL-2 lymphoma target cells was also observed for nonelicited resident peritoneal macrophages from mice injected intramuscularly with MnC12. There were no differences in the cellularity or relative number of adherent cells obtained from the peritoneal cavity of saline or MnC12-injected mice. These enhanced macrophage functions were associated with the induction of increased interferon levels in mice injected with MnC12.