Effects of recombinant interferon-gamma and chemotherapy with isoniazid and rifampicin on infections of mouse peritoneal macrophages with Listeria monocytogenes and Mycobacterium microti in vitro.
The effect of recombinant murine interferon-gamma (IFN-gamma) on the growth of Listeria monocytogenes for 4 h and Mycobacterium microti for up to 3 days in monolayers of peritoneal macrophages from BALB/c mice was examined by serial viable counts of cell-associated bacteria. Macrophages pretreated with 10 u IFN-gamma per ml were bacteriostatic and with 100 u or 1000 u per ml were bactericidal against L. monocytogenes. Addition of IFN-gamma 3 days before infection caused monolayers to be bactericidal against M. microti mainly during the first 15 min after infection. This was just evident with 10 u IFN-gamma per ml and greater with 100 u or 1000 u per ml. If IFN-gamma was added when phagocytosis of M. microti was complete, about 2 h after infection, its action was only bacteriostatic, the viable counts remaining stationary while those of unexposed monolayers increased. IFN-gamma 100 u per ml added before infection did not alter the bactericidal activity of rifampicin 10 mg/l, nor did it alter the killing curves for isoniazid 1 mg/l or for rifampicin 10 mg/l if added after completion of phagocytosis.
D000818:Animals; D001424:Bacterial Infections / Q000188:drug therapy*; D002478:Cells, Cultured; D004359:Drug Therapy, Combination; D007371:Interferon-gamma / Q000627:therapeutic use*; D007538:Isoniazid / Q000627:therapeutic use*; D008088:Listeriosis / Q000188:drug therapy; D008222:Lymphokines / Q000627:therapeutic use*; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009164:Mycobacterium Infections / Q000188:drug therapy; D011994:Recombinant Proteins / Q000627:therapeutic use; D012293:Rifampin / Q000627:therapeutic use*
D008222:Lymphokines; D011994:Recombinant Proteins; D007371:Interferon-gamma; D007538:Isoniazid; D012293:Rifampin