title: Leishmania donovani infection enhances macrophage viability in the absence of exogenous growth factor.
abstract: Bone marrow-derived macrophages rapidly die in the absence of macrophage growth factor (M-CSF). However, as demonstrated here, bone marrow-derived macrophages infected with Leishmania donovani exhibit increased viability in the absence of exogenous growth factor. Forty-eight hours after inoculation with promastigotes or amastigotes, infected cell cultures contained 180 and 95% more cells, respectively, than control cultures. This effect was specific to Leishmania infection, as uptake of latex beads or avirulent promastigotes by macrophages did not enhance cell viability. L. donovani-infected macrophages also displayed increased phagocytic capacity, as compared with control macrophages and macrophages grown continuously in M-CSF-containing medium. Supernatants collected from infected cells elaborated a factor(s) that enhanced macrophage viability but did not stimulate macrophage DNA synthesis. This activity of L. donovani-infected cell-conditioned medium could be abrogated by preincubation of macrophages with cycloheximide before inoculation with the parasite, implying that macrophage protein synthesis is required for the elaboration of this factor(s).
authors.affiliation: Institute of Parasitology, McGill University, Ste. Anne-de-Bellevue, Quebec, Canada.
authors.forename: K J
authors.initials: KJ
authors.lastname: Moore
authors.forename: S J
authors.initials: SJ
authors.lastname: Turco
authors.forename: G
authors.initials: G
authors.lastname: Matlashewski
mesh_terms: D000818:Animals; D002470:Cell Survival; D002478:Cells, Cultured; D006224:Cricetinae; D004247:DNA / Q000096:biosynthesis; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000502:physiology; D006133:Growth Substances / Q000494:pharmacology*; D007893:Leishmania donovani; D007898:Leishmaniasis, Visceral / Q000276:immunology*; D008264:Macrophages / Q000469:parasitology / Q000502:physiology*; D008647:Mesocricetus; D051379:Mice; D008807:Mice, Inbred BALB C; D010587:Phagocytosis; D014176:Protein Biosynthesis
chemical_list: D006133:Growth Substances; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D004247:DNA