Macrophage response to viruses, protozoa, and fungi: secretory and cellular activities induced in resting unprimed bone marrow-derived mononuclear phagocytes.

The secretory (tumor necrosis factor, TNF-alpha; nitrite) and cellular response (mitochondrial respiration, TNF-alpha-independent tumoricidal activity) of a pure, lymphocyte-free population of resting, unprimed rat bone marrow-derived mononuclear phagocytes (BMM phi) to direct interaction with viruses, protozoa, and fungi was assessed and compared with that triggered by bacterial agents and interferon-gamma (IFN-gamma). Viruses (herpes simplex, vaccinia, poliomyelitis, vesicular stomatitis, lymphocytic choriomeningitis, Sendai), protozoa (Trypanosoma brucei, Giardia lamblia), and fungi (Penicillium, Trichosporon, Fusarium, Rhizopus, Aspergillus, Geotrichum species) affected primarily the secretion of TNF-alpha and mitochondrial respiration of BMM phi; their effects on the secretion of nitrite and on tumoricidal activity were at best marginal. Collectively, the macrophage response to viruses, protozoa, and fungi was less varied and less marked than that to bacterial agents (intact organisms, peptidoglycan, lipoteichoic acid, lipopolysaccharide) and IFN-gamma.