title: In vitro and in vivo activation of human mononuclear phagocytes by interferon-gamma. Studies with normal and AIDS monocytes.
abstract: To determine the potential immunotherapeutic role of interferon-gamma (IFN-gamma) as a mononuclear phagocyte-activating agent, we examined the effector cell function of peripheral blood monocytes from healthy donors and acquired immunodeficiency syndrome (AIDS) patients after either in vitro and/or in vivo treatment with recombinant (r) IFN-gamma. When assayed immediately after a 24-hr in vitro pulse with 300 U/ml, normal and AIDS monocytes behaved similarly with little augmentation of their intrinsically high levels of H2O2 release and activity against Toxoplasma gondii; in contrast, activity toward the more resistant intracellular pathogen, Leishmania donovani, was appreciably enhanced by rIFN-gamma. In addition, upon testing 4 to 6 days after in vitro pulsing, both normal and AIDS monocytes showed clear evidence of persistent activation in all three assays. The capacity of IFN-gamma to similarly activate monocytes in vivo was confirmed in all ten treated AIDS patients by examining cells before and after 24-hr infusions of 0.03 and 0.5 mg of rIFN-gamma/square meter (M2) of body surface area. For postinfusion monocytes tested after 1 day in culture, H2O2 release and antitoxoplasma activity were essentially unchanged, but antileishmanial effects were augmented. After 5 to 7 days in culture, monocytes from treated patients showed 3.2- to 5.9-fold increases in H2O2-releasing capacity and increases of 49 to 68% and 35 to 61% in intracellular activity against T. gondii and L. donovani, respectively. These results indicate that the human monocyte can be induced by rIFN-gamma to express signs of both immediate and persistent activation and suggest that, as a direct activator of mononuclear phagocytes, rIFN-gamma may also have potential as an immunotherapeutic agent for patients with intracellular infections.
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D000328:Adult; D000818:Animals; D002478:Cells, Cultured; D006801:Humans; D006861:Hydrogen Peroxide / Q000096:biosynthesis; D007371:Interferon-gamma / Q000494:pharmacology* / Q000627:therapeutic use; D007891:Leishmania; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects*; D008297:Male; D009000:Monocytes / Q000187:drug effects*; D010587:Phagocytosis / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology / Q000627:therapeutic use; D013268:Stimulation, Chemical; D014122:Toxoplasma
chemical_list: D011994:Recombinant Proteins; D007371:Interferon-gamma; D006861:Hydrogen Peroxide