title: Synergic inhibitory activity of amphotericin-B and gamma interferon against intracellular Cryptococcus neoformans in murine macrophages.
abstract: Cryptococcus neoformans is responsible for pulmonary and meningal infections in HIV patients. The lack of effective cellular cooperation caused by the low level of CD4+ cells, and the resistance of C. neoformans to phagocytosis allows growth and persistence of the yeast in the host. We describe here an in-vitro model of intracellular replication of C. neoformans inside J774-A.1 macrophages, and the determination of the intracellular antifungal activity of amphotericin B and fluconazole alone or in association with IFN-gamma. The maximum inhibitory effect was observed with one MIC of amphotericin B and 100 or 1000 IU/mL of IFN-gamma. amphotericin B alone (at 1 x MIC), or either 1 x or 50 x MIC of fluconazole in normal or IFN-gamma activated macrophages, did not eradicate the ingested yeast. A potential underlying mechanism of the synergy of amphotericin B in IFN-gamma primed macrophages was investigated by measurement of nitrite level and by use of the NO synthase competitive inhibitor, NG-monomethyl L-arginine (NMMA). One MIC of amphotericin B was able to activate the synthesis of nitrogen reactive intermediates in IFN gamma-primed macrophages. NMMA treated infected macrophages responded less well to IFN-gamma priming, resulting in a moderate inhibition in subsequent amphotericin B exposure.
authors.affiliation: Laboratoire de Microbiologie, Hopital Hotel Dieu, Paris, France.
authors.forename: J L
authors.initials: JL
authors.lastname: Herrmann
authors.forename: N
authors.initials: N
authors.lastname: Dubois
authors.forename: M
authors.initials: M
authors.lastname: Fourgeaud
authors.forename: D
authors.initials: D
authors.lastname: Basset
authors.forename: P H
authors.initials: PH
authors.lastname: Lagrange
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D003455:Cryptococcus neoformans / Q000187:drug effects* / Q000378:metabolism; D004357:Drug Synergism; D015725:Fluconazole / Q000494:pharmacology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects / Q000382:microbiology*; D051379:Mice; D008826:Microbial Sensitivity Tests; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000096:biosynthesis
chemical_list: D009569:Nitric Oxide; D000666:Amphotericin B; D007371:Interferon-gamma; D015725:Fluconazole