The Journal of Experimental Medicine
Accuri Cytometers
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

Published online 10 April 2006 doi:10.1084/jem.20051659
Rockefeller University Press, 0022-1007 $8.00
JEM, Volume 203, Number 4, 1093-1104
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow PPT slides of all figures
Right arrow Supplemental Material Index
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JEM
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Molofsky, A. B.
Right arrow Articles by Swanson, M. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Molofsky, A. B.
Right arrow Articles by Swanson, M. S.
Right arrowPubmed/NCBI databases
*Gene*GEO Profiles
*HomoloGene*UniGene
*Substance via MeSH
Related Collections
Right arrowRelated Article
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

ARTICLE

Cytosolic recognition of flagellin by mouse macrophages restricts Legionella pneumophila infection

Ari B. Molofsky1, Brenda G. Byrne1, Natalie N. Whitfield1, Cressida A. Madigan1, Etsu T. Fuse2, Kazuhiro Tateda2, and Michele S. Swanson1

1 Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
2 Department of Microbiology and Infectious Diseases, Toho University School of Medicine, Ohtaku, Tokyo 143-8540, Japan

CORRESPONDENCE Michele S. Swanson: mswanson{at}umich.edu

To restrict infection by Legionella pneumophila, mouse macrophages require Naip5, a member of the nucleotide-binding oligomerization domain leucine-rich repeat family of pattern recognition receptors, which detect cytoplasmic microbial products. We report that mouse macrophages restricted L. pneumophila replication and initiated a proinflammatory program of cell death when flagellin contaminated their cytosol. Nuclear condensation, membrane permeability, and interleukin-1ß secretion were triggered by type IV secretion-competent bacteria that encode flagellin. The macrophage response to L. pneumophila was independent of Toll-like receptor signaling but correlated with Naip5 function and required caspase 1 activity. The L. pneumophila type IV secretion system provided only pore-forming activity because listeriolysin O of Listeria monocytogenes could substitute for its contribution. Flagellin monomers appeared to trigger the macrophage response from perforated phagosomes: once heated to disassemble filaments, flagellin triggered cell death but native flagellar preparations did not. Flagellin made L. pneumophila vulnerable to innate immune mechanisms because Naip5+ macrophages restricted the growth of virulent microbes, but flagellin mutants replicated freely. Likewise, after intratracheal inoculation of Naip5+ mice, the yield of L. pneumophila in the lungs declined, whereas the burden of flagellin mutants increased. Accordingly, macrophages respond to cytosolic flagellin by a mechanism that requires Naip5 and caspase 1 to restrict bacterial replication and release proinflammatory cytokines that control L. pneumophila infection.


Abbreviations used: ASC, apoptosis-associated specklike protein; CFP, crude flagellar preparation; LDH, lactate dehydrogenase; LLO, listeriolysin O; LRR, leucine-rich repeat; MOI, multiplicity of infection; NOD, nucleotide-binding oligomerization domain; PAMP, pathogen-associated molecular pattern; PE, postexponential; TLR, Toll-like receptor.

C.A. Madigan's present address is Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?

Related Article

The perils of locomotion
Heather L. Van Epps
J. Exp. Med. 2006 203: 801. [Full Text] [PDF]



This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search
TABLE OF CONTENTS