Document Detail


Haemolysin II is a Bacillus cereus virulence factor that induces apoptosis of macrophages.
MedLine Citation:
PMID:  20731668     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
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.
Authors:
Seav-Ly Tran; Elisabeth Guillemet; Maud Ngo-Camus; Cyril Clybouw; Andrea Puhar; Arnaud Moris; Michel Gohar; Didier Lereclus; Nalini Ramarao
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Cellular microbiology     Volume:  13     ISSN:  1462-5822     ISO Abbreviation:  Cell. Microbiol.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2010-12-20     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883691     Medline TA:  Cell Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  92-108     Citation Subset:  IM    
Copyright Information:
© 2010 Blackwell Publishing Ltd.
Affiliation:
INRA, Unité MICALIS, UMR 1319, équipe GME, La Minière, 78285 Guyancourt, France.
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