Serologic expression cloning has identified flagellins of the intestinal microbiota as immunodominant antigens in experimental colitis in mice and in individuals with Crohn's disease.
Dr Charles Elson and colleagues from the United Kingdom identified the microbial source of such flagellins.
|The bacteria fall into the family Lachnospiraceae|
|Inflammatory Bowel Diseases|
Using a variety of isolation and culture approaches, the researchers isolated a number of previously unknown flagellated bacteria.
The team assessed 16S ribosomal DNA sequences, and found that these bacteria fall into the family Lachnospiraceae of the phylum Firmicutes.
The researchers found serum IgG from patients with Crohn's disease and from mice with colitis reacted to the flagellins of these bacteria.
Serum IgG from controls did not did not react to the flagellins of the isolated bacteria.
The team found that the sequence of these flagellins demonstrate conserved amino- and carboxy-terminal domains that cluster phylogenetically.
The flagellins have a predicted 3D structure similar to Salmonella fliC, including an intact TLR5 binding site.
The research team noted that the flagellin of 1 of these bacteria was likely O-glycosylated.
Dr Elson's team concluded, "The conserved immune response in both mouse and human to these previously unknown flagellins of the microbiota indicate that they play an important role in host-microbe interactions in the intestine."