Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Intestine crucial to function of immune cells, research shows

13.12.2011
Researchers 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 cells—a type of white blood cell that produces antibodies—acquire 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 immunology—based mostly on research done in the spleen, lymph nodes or other sterile sites distant from gut microbes—has 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. Jörg Fritz, Olga Rojas and Doug McCarthy, found that as B cells differentiate into plasma cells in the gut, they adopt characteristics of innate immune cells—despite their traditional association with the adaptive immune system. Specifically, they begin to look and act like inflammatory cells called monocytes, while maintaining their ability to produce a key antibody called Immunoglobulin A.

"What intrigued us was that this theme—B cells behaving like monocytes—had been seen before in fish and in vitro. But now we have a living example in a mammalian system, where this kind of bipotentiality is realized," said Prof. Gommerman.

This B-cell plasticity provides a potential explanation how cells dedicated to controlling pathogens can respond to a large burden of harmful bacteria without damaging beneficial bacteria and other cells essential for proper function of the intestine.

It also may explain how scientists had failed to appreciate the multi-functionality of some B cells. "There are classical markers immunologists use to identify B cells—receptors that are displayed on their surface—and most of them are absent from plasma cells," said Prof. Gommerman. "So in some cases, what people thought was a monocyte could have been a plasma cell because it had changed its surface identity, although monocytes play an important role in innate immunity as well."

This transformational ability, the researchers also found, is dependent on bacteria called commensal microflora that digests food and provides nutrients. That relationship highlights the importance of the gut in fighting infection, and begs the question of whether plasma cells trained in the gut to secrete specific anti-microbial molecules can play a role in other infectious disease scenarios, such as food-borne listeria infection.

It also opens a line of investigation into whether a systemic relationship exists between those anti-microbial molecules and healthy cells in sites remote from the intestine. Understanding the nature of that relationship could improve understanding of inflammatory mechanisms in autoimmune disorders such as lupus, rheumatoid arthritis and multiple sclerosis, in which immune cells attack and eventually destroy healthy tissue.

But the next step, said Prof. Gommerman, is to look at human samples for the same type of multi-potentiality they saw in rodent plasma cells that acquired their anti-microbial properties in the gut.

"We're really at the early stages of understanding what we call the microbiome in the gut," said Prof. Gommerman. "There is a role for plasma cells in many autoimmune diseases, and B cells can do a lot more than just make antibodies. We need to understand the full spectrum of their effects within the immune response."

The study was funded by the Canadian Institutes of Health Research, the Canada Foundation for Innovation, the Ontario Research Fund, the Austrian Academy of Sciences and the National Institutes of Health.

About the University of Toronto

Established in 1827, the University of Toronto has assembled one of the strongest research and teaching faculties in North America, presenting top students at all levels with an intellectual environment unmatched in breadth and depth on any other Canadian campus. U of T faculty co-author more research articles than their colleagues at any university in the US or Canada other than Harvard. As a measure of impact, U of T consistently ranks alongside the top five U.S. universities whose discoveries are most often cited by other researchers around the world. U of T faculty are also widely recognized for their teaching strengths and commitment to graduate supervision. www.utoronto.ca.

Jim Oldfield | EurekAlert!
Further information:
http://www.utoronto.ca

More articles from Health and Medicine:

nachricht Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University

nachricht Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>