Haemolysin II is a Bacillus cereus virulence factor that induces apoptosis of macrophages.
Cell Microbiol
; 13(1): 92-108, 2011 Jan.
Article
em En
| MEDLINE
| ID: mdl-20731668
ABSTRACT
Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation despite the recruitment of phagocytic cells. The precise mechanisms and the bacterial factors allowing B. cereus to circumvent host immune responses remain to be elucidated. We have previously shown that B. cereus induces macrophage cell death by an unknown mechanism. Here we identified the toxic component from the B. cereus supernatant. We report that Haemolysin II (HlyII) provokes macrophage cell death by apoptosis through its pore-forming activity. The HlyII-induced apoptotic pathway is caspase 3 and 8 dependent, thus most likely mediated by the death receptor pathway. Using insects and mice as in vivo models, we show that deletion of hlyII strongly reduces virulence. In addition, we show that after infection of Bombyx mori larvae, the immune cells are apoptotic, demonstrating that HlyII induces apoptosis of phagocytic cells in vivo. Altogether, our results clearly unravel HlyII as a novel virulence protein that induces apoptosis in phagocytic cells in vitro and in vivo.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bacillus cereus
/
Proteínas de Bactérias
/
Apoptose
/
Fatores de Virulência
/
Proteínas Hemolisinas
/
Macrófagos
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Female
/
Humans
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article