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 Molecular evolution: How the building blocks of life may form in space
26.04.2018 | American Institute of Physics

nachricht Multifunctional bacterial microswimmer able to deliver cargo and destroy itself
26.04.2018 | Max-Planck-Institut für Intelligente Systeme

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>