Specialized Immune Cells Use Vitamin B To Recognize Infection

Researchers have discovered how specialized immune cells recognize products of vitamin B synthesis that are unique to bacteria and yeast, triggering the body to fight infection.

AsianScientist (Oct. 16, 2012) – An Australian research team has discovered how specialized immune cells recognize products of vitamin B synthesis that are unique to bacteria and yeast, triggering the body to fight infection.

The study, jointly led by researchers at the University of Melbourne and Monash University and published in the journal Nature, has revealed for the first time that the highly abundant mucosal associated invariant T cells (MAIT cells) recognize products of vitamin B synthesis from bacteria and yeast and use that to activate the immune system.

The research revealed how by-products of bacterial vitamin synthesis, including some derived from folic acid or vitamin B9 and riboflavin or vitamin B2, could be captured by the immune receptor MR1 thus fine-tuning the activity of MAIT cells.

“Humans are unable to make vitamin B and obtain it mostly from diet. Because bacteria can synthesize vitamin B, our immune system uses this as a point of difference to recognize infection,” said Dr. Lars Kjer-Nielsen from the University of Melbourne who led the five-year study.

“Given the relative abundance of the MAIT cells lining mucosal and other surfaces, such as the intestine, the mouth, lungs, it is quite probable that they play a protective role in many infections from thrush to tuberculosis. This is a significant discovery that unravels the long sought target of MAIT cells and their role in immunity to infection,” he said.

Monash University’s Professor Jamie Rossjohn said the findings had major implications for understanding the interplay between gut bacteria and the immune system. “Some vitamin by-products appear to drive immunity while others dampen it,” she said.

The authors say that the next step is to explore whether MAIT cells might also be involved in intestinal or mucosal disorders such as inflammatory bowel disease and irritable bowel syndrome. The findings may also open up potential targets to improve treatments or to develop a vaccine for tuberculosis.

The article can be found at: Kjer-Nielsen L et al. (2012) MR1 presents microbial vitamin B metabolites to MAIT cells.

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Source: University of Melbourne.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Anusuya Das received a Ph.D. in Biological Engineering from Massachusetts Institute of Technology (MIT), USA, and a B.A. in Bioelectrical/Cellular-Molecular Engineering from Arizona State University, USA. Anusuya is currently a post-doctoral researcher at the University of Virginia, USA.

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