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 Finding new clues to brain cancer treatment
21.02.2020 | Case Western Reserve University

nachricht UIC researchers find unique organ-specific signature profiles for blood vessel cells
18.02.2020 | University of Illinois at Chicago

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: High-pressure scientists in Bayreuth discover promising material for information technology

Researchers at the University of Bayreuth have discovered an unusual material: When cooled down to two degrees Celsius, its crystal structure and electronic properties change abruptly and significantly. In this new state, the distances between iron atoms can be tailored with the help of light beams. This opens up intriguing possibilities for application in the field of information technology. The scientists have presented their discovery in the journal "Angewandte Chemie - International Edition". The new findings are the result of close cooperation with partnering facilities in Augsburg, Dresden, Hamburg, and Moscow.

The material is an unusual form of iron oxide with the formula Fe₅O₆. The researchers produced it at a pressure of 15 gigapascals in a high-pressure laboratory...

Im Focus: From China to the South Pole: Joining forces to solve the neutrino mass puzzle

Study by Mainz physicists indicates that the next generation of neutrino experiments may well find the answer to one of the most pressing issues in neutrino physics

Among the most exciting challenges in modern physics is the identification of the neutrino mass ordering. Physicists from the Cluster of Excellence PRISMA+ at...

Im Focus: Therapies without drugs

Fraunhofer researchers are investigating the potential of microimplants to stimulate nerve cells and treat chronic conditions like asthma, diabetes, or Parkinson’s disease. Find out what makes this form of treatment so appealing and which challenges the researchers still have to master.

A study by the Robert Koch Institute has found that one in four women will suffer from weak bladders at some point in their lives. Treatments of this condition...

Im Focus: A step towards controlling spin-dependent petahertz electronics by material defects

The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.

Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...

Im Focus: Freiburg researcher investigate the origins of surface texture

Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.

Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

70th Lindau Nobel Laureate Meeting: Around 70 Laureates set to meet with young scientists from approx. 100 countries

12.02.2020 | Event News

11th Advanced Battery Power Conference, March 24-25, 2020 in Münster/Germany

16.01.2020 | Event News

Laser Colloquium Hydrogen LKH2: fast and reliable fuel cell manufacturing

15.01.2020 | Event News

 
Latest News

Turbomachine expander offers efficient, safe strategy for heating, cooling

25.02.2020 | Power and Electrical Engineering

The seismicity of Mars

25.02.2020 | Earth Sciences

Cancer cachexia: Extracellular ligand helps to prevent muscle loss

25.02.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>