title: Apoptosis of murine peritoneal macrophages induced by an avian pathogenic strain of Escherichia coli.
abstract: The mechanisms used by avian strains of Escherichia coli to invade the respiratory epithelia, leading to septicemia in poultry, are not well-established. In this work, we show that resident murine peritoneal macrophages infected in vitro with an avian strain of E. coli underwent apoptosis 4 h after infection (55.6% of apoptosis in infected cells versus 3.5% in non-infected cells). Heat-inactivated bacteria did not induce apoptosis and the inhibition of phagocytosis by pretreatment of cells with cytochalasin D reduced the number of apoptotic cells from 55.6 to 13.9% (P<0.05), showing that the bacteria must be intracellularly located and viable to induce apoptosis. Therefore, these data suggest that induction of macrophage apoptosis may be a pathogenic mechanism employed by avian E. coli to circumvent the host defences and invade the respiratory epithelia.
authors.affiliation: Departamento de Patologia Geral, Universidade Estadual de Londrina, Londrina, Brazil.
authors.forename: V S
authors.initials: VS
authors.lastname: Rodrigues
authors.forename: M C
authors.initials: MC
authors.lastname: Vidotto
authors.forename: I
authors.initials: I
authors.lastname: Felipe
authors.forename: D S
authors.initials: DS
authors.lastname: Santos
authors.forename: L C
authors.initials: LC
authors.lastname: Gaziri
mesh_terms: D000818:Animals; D017209:Apoptosis; D002478:Cells, Cultured; D002645:Chickens; D004926:Escherichia coli / Q000472:pathogenicity / Q000502:physiology*; D004927:Escherichia coli Infections / Q000503:physiopathology / Q000662:veterinary; D020287:In Situ Nick-End Labeling; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000382:microbiology* / Q000502:physiology*; D051379:Mice; D010587:Phagocytosis; D011201:Poultry Diseases / Q000382:microbiology / Q000503:physiopathology; D012763:Shigella flexneri / Q000502:physiology