Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New network of gastrointestinal immune cells discovered

14.01.2005


Findings could lead to new vaccines and antibacterial strategies

A previously unknown network of immune cells has been discovered in the mammalian gastrointestinal system by a research group based in the Center for the Study of Inflammatory Bowel Diseases at Massachusetts General Hospital (MGH). The finding, reported in the January 14 issue of Science, could lead to better understanding of how the immune system recognizes and responds to dangerous bacteria and viruses and to new approaches to immunization and infectious disease treatment.

"We found an extensive system of immune cells throughout the intestinal tract that take up bacteria and other antigens, giving us a new target for understanding the immune response," says Hans-Christian Reinecker, MD, of the MGH Gastrointestinal Unit, the study’s senior author.



The investigation focused on dendritic cells which are found in tissues in direct contact with the external environment, such as the skin, lungs and digestive system. Characterized by long extensions called dendrites, dendritic cells continually sample their environment for bacteria and viruses. When dendritic cells encounter pathogens, they ingest them, break them down and then transport protein fragments to the cellular membrane. On the cells’ surface the fragments are displayed to other immune system cells, which will recognize the proteins as antigens to be destroyed.

Exactly how dendritic cells monitor intestinal contents and recognize harmful organisms was unknown, and learning more about that process was a goal of the current study. The researchers conducted several experiments using genetically altered mice in which one or both copies of a gene required for cell migration and dendrite formation was replaced with a gene that produces a fluorescent protein. Examination of the animals’ tissues revealed populations of dendritic cells throughout the small intestine in a layer just below the epithelial lining. It previously had been believed that gastrointestinal dendritic cells were few in number and restricted to specialized immune organs called Peyer’s patches.

Three-dimensional computer-assisted tissue reconstruction allowed detailed microscopic examination of the intestinal tissues, which showed that dendrites extend from the dendritic cells through the epithelial layer, giving them direct access to intestinal contents. In animals without the gene required for normal dendrite growth – which produces a receptor protein – dendrites formed but did not penetrate the epithelium. Dendritic cells without access to the interior of the intestine were not able to carry out one of their normal functions, taking up the harmless strains of E. coli that normally populate the intestine and transporting them to lymph nodes.

Introduction of disease-causing salmonella bacteria into the gastrointestinal system of both groups of mice revealed that the receptor-negative animals, whose dendritic cells could not effectively sample intestinal contents, were unable to mount an effective immune defense and developed extensive salmonella infection.

"This is a new way for the immune system in the gastrointestinal tract to monitor and interact with the environment," says Reinecker, an assistant professor of Medicine at Harvard Medical School. "Insights into these mechanisms could lead to better understanding of conditions such as Crohn’s Disease and ulcerative colitis, intestinal infections and food allergy. Targeting these dendritic cells also could help us develop new types of vaccines. And it’s possible that some of the gastrointestinal bacteria and viruses that cause serious illness may co-opt the activity of these cells to enter the body and bypass some immune defenses."

Sue McGreevey | EurekAlert!
Further information:
http://www.mgh.harvard.edu

More articles from Life Sciences:

nachricht Water forms 'spine of hydration' around DNA, group finds
26.05.2017 | Cornell University

nachricht How herpesviruses win the footrace against the immune system
26.05.2017 | Helmholtz-Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

How herpesviruses win the footrace against the immune system

26.05.2017 | Life Sciences

Water forms 'spine of hydration' around DNA, group finds

26.05.2017 | Life Sciences

First Juno science results supported by University of Leicester's Jupiter 'forecast'

26.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>