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Isolation of flagellated bacteria implicated in Crohn's disease
L Wayne Duck1, Mark R Walter, Jan Novak
1Division of Gastroenterology and Hepatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294-0007, USA.
Inflammatory Bowel Diseases
|August 23, 2007
Summary
Researchers identified previously unknown flagellated bacteria in the gut. Their flagellins trigger immune responses in Crohn's disease patients and colitis models, highlighting their role in gut inflammation.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Flagellins from intestinal microbiota are key antigens in experimental colitis and Crohn's disease (CD).
- The specific microbial source of these immunodominant flagellins remained unidentified.
Purpose of the Study:
- To identify the microbial origin of flagellins recognized in experimental colitis and human Crohn's disease.
- To characterize the identified flagellins and their immune properties.
Main Methods:
- Employed diverse isolation and culture techniques to obtain novel flagellated bacteria.
- Utilized 16S ribosomal DNA sequencing for bacterial identification and phylogenetic analysis.
- Analyzed serum IgG reactivity from Crohn's disease patients and colitis models against bacterial flagellins.
Main Results:
- Isolated previously unknown flagellated bacteria belonging to the Lachnospiraceae family (phylum Firmicutes).
- Demonstrated specific reactivity of serum IgG from CD patients and colitis models to these novel flagellins, with no reactivity from controls.
- Flagellin sequences revealed conserved domains, phylogenetic clustering, and structural similarity to Salmonella fliC, including a functional TLR5 binding site. O-glycosylation was observed in one flagellin.
Conclusions:
- These findings reveal a conserved immune response in both mice and humans to previously unknown flagellins.
- These flagellins are significant players in host-microbe interactions within the intestine.
- The identified flagellins represent potential targets for understanding and managing inflammatory conditions like Crohn's disease.
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