In the study conducted using mouse model, the researchers found that ytophaga-flavobacter-bacteroidetes (CFB) bacteria were associated with the creation of Th17 cells.
The bacteria play a crucial role in digestion and protect against pathogens by outcompeting harmful bacteria.
"It's not the amount of microbial flora but the kind of microbial flora that seems to count," said Dr. Dan Littman, NYU School of Medicine.
He said that identifying the specific species of bacteria that influence the balance of inflammatory cells, could lead to more sophisticated treatments that fine-tune bacteria in the intestine and, in turn, dampen the production of inflammatory cells.
During the study, Littman's team observed that newborn mice that remain isolated from bacteria never generate any of these cells. They begin to generate the cells only after they begin to eat food and ingest bacteria.
These observations suggested that the introduction of bacteria in the gut is associated with the creation of Th17 cells.
For the study, the team gave normal, bacteria-filled mice antibiotics that selectively killed some of the bacteria in their small intestine. Some of these antibiotics also depleted their Th17 cells, indicating for the first time a causal link between specific bacteria and the generation of inflammatory cells.
They found a colony of mice that have intestinal bacteria but do not have Th17 cells. It had different bacteria in their guts than other colonies.
By comparing the intestinal bacteria in mice, the team discovered that cytophaga-flavobacter-bacteroidetes (CFB) bacteria were associated with the creation of Th17 cells.
"There is more and more evidence that gut flora have a tremendously important influence on human health," said Yasmine Belkaid, Ph.D., chief of the mucosal immunology unit in the laboratory of parasitic diseases at the National Institutes of Health
"If some set of microbes induces a specific immune response, this points to a way to manipulate the immune system," says Dr. Belkaid.
This new study is the first report that has associated a defined set of gut flora with the induction of specific immune cells," she added.
The study is published in the October 16 issue of the journal Cell Host and Microbe.