title: Preactivation of macrophages in mice acutely infected with Schistosoma mansoni.
abstract: This paper shows that peritoneal murine macrophages become preactivated in vivo during the course of a Schistosoma mansoni infection. Thus, less macrophage-activating factor (MAF) was required to induce in vitro tumoricidal and schistosomulicidal activity in macrophages from S. mansoni-infected mice than in macrophages from uninfected control animals. Moreover, the respiratory burst activity, as measured by chemiluminescence, was enhanced in macrophages from S. mansoni-infected mice as compared to controls, whether or not lymphokine (LK) was present in the macrophage cultures. This response appeared at 3 weeks and persisted at least until 12 weeks after infection. Interferon-gamma (IFN-gamma) is most likely involved in the mechanisms leading to such an increased cytolytic and oxidative activity, since in vitro experiments showed: 1) that less IFN-gamma was required to induce tumoricidal activity in macrophages from infected as compared to macrophages from uninfected animals, 2) that the activity of (2'-5')-adenylate synthetase (2'-5' A-synthetase), an enzyme strongly induced by IFN, was elevated in cells from livers of S. mansoni-infected mice.
mesh_terms: D000818:Animals; D003602:Cytotoxicity, Immunologic; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D008222:Lymphokines / Q000494:pharmacology; D008262:Macrophage Activation; D016215:Macrophage-Activating Factors; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010100:Oxygen / Q000378:metabolism; D010529:Peritoneal Cavity / Q000166:cytology; D012555:Schistosomiasis mansoni / Q000276:immunology*
chemical_list: D008222:Lymphokines; D016215:Macrophage-Activating Factors; D007371:Interferon-gamma; D010100:Oxygen