Format

Send to

Choose Destination
Science. 2011 May 20;332(6032):974-7. doi: 10.1126/science.1206095. Epub 2011 Apr 21.

The Toll-like receptor 2 pathway establishes colonization by a commensal of the human microbiota.

Author information

1
Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA. jround@caltech.edu

Abstract

Mucosal surfaces constantly encounter microbes. Toll-like receptors (TLRs) mediate recognition of microbial patterns to eliminate pathogens. By contrast, we demonstrate that the prominent gut commensal Bacteroides fragilis activates the TLR pathway to establish host-microbial symbiosis. TLR2 on CD4(+) T cells is required for B. fragilis colonization of a unique mucosal niche in mice during homeostasis. A symbiosis factor (PSA, polysaccharide A) of B. fragilis signals through TLR2 directly on Foxp3(+) regulatory T cells to promote immunologic tolerance. B. fragilis lacking PSA is unable to restrain T helper 17 cell responses and is defective in niche-specific mucosal colonization. Therefore, commensal bacteria exploit the TLR pathway to actively suppress immunity. We propose that the immune system can discriminate between pathogens and the microbiota through recognition of symbiotic bacterial molecules in a process that engenders commensal colonization.

Comment in

PMID:
21512004
PMCID:
PMC3164325
DOI:
10.1126/science.1206095
[Indexed for MEDLINE]
Free PMC Article

Publication types, MeSH terms, Substances, Grant support

Publication types

MeSH terms

Substances

Grant support

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center