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 Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign

nachricht Rabies viruses reveal wiring in transparent brains
19.01.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>