TORONTO, CanadaResearchers at the University of Toronto have found an explanation for how the intestinal tract influences a key component of the immune system to prevent infection, offering a potential clue to the cause of autoimmune disorders like rheumatoid arthritis and multiple sclerosis.
"The findings shed light on the complex balance between beneficial and harmful bacteria in the gut," said Prof. Jennifer Gommerman, an Associate Professor in the Department of Immunology at U of T, whose findings were published online by the scientific journal, Nature. "There has been a long-standing mystery of how certain cells can differentiate between and attack harmful bacteria in the intestine without damaging beneficial bacteria and other necessary cells. Our research is working to solve it."
The researchers found that some B cellsa type of white blood cell that produces antibodiesacquire functions that allow them to neutralize pathogens only while spending time in the gut. Moreover, this subset of B cells is critical to health.
"When we got rid of that B-cell function, the host was unable to clear a gut pathogen and there were other negative outcomes, so it appears to be very important for the cells to adopt this function in the gut," said Prof. Gommerman, whose lab conducted the research in mice.
Textbook immunologybased mostly on research done in the spleen, lymph nodes or other sterile sites distant from gut microbeshas suggested that B cells develop a specific immune function and rigidly maintain that identity. Over the last few years, however, some labs have shown the microbe-rich environment of the gut can induce flexibility in immune cell identity.
Prof. Gommerman and her colleagues, including trainees from her lab Drs. Jrg Fritz, Olga Rojas and Doug McCarthy, found that as B cells differentiate into plasma cells in the gut, they adopt characteristics of innate immune cellsdespite their traditional associat
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University of Toronto