Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Choice between two evils

13.06.2012
Multiple sclerosis continues to puzzle scientists in all sorts of ways. Now researchers from the University of Würzburg have managed to make some progress in the search for the causes of this disease. They have revealed that in order to avoid greater damage the brain accepts a lesser evil.

The “disease with 1000 faces” is how multiple sclerosis (MS) is sometimes described. The reason for this name is that the clinical picture can differ dramatically from patient to patient – in terms of both the progression of the disease and the symptoms suffered.

However, there is one finding that is the same in principle for everyone: multiple sclerosis is an autoimmune disease where one particular type of brain cell, known as an oligodendrocyte, is destroyed by the immune system. Oligodendrocytes form an insulating layer around the extensions of nerve cells that is required for efficient impulse conduction.

If this conduction is disturbed as a consequence of damage to the insulating layer, the nerves cannot transfer relevant “messages” as effectively as before. This is why multiple sclerosis sufferers often feel a tingling sensation in their extremities. Patients stumble more or have difficulties seeing. In extreme cases, they become incapable of moving around on their own and are confined to a wheelchair. According to the Multiple Sclerosis Society of Germany, around 2.5 million people worldwide have MS. The latest projections indicate that some 130,000 sufferers live in Germany; around 2,500 people are diagnosed with the disease each year.

Killer T cells are suspected of being a cause

The full details of what triggers the onset of the disease are not yet known. “Based on tests done on the brains of deceased MS patients, it has long been suspected that a certain type of lymphocyte, the killer T cell, is involved in destroying oligodendrocytes,” says Professor Thomas Hünig from the Institute of Virology and Immunobiology at the University of Würzburg. Together with scientists from Cologne and Dresden, Hünig and his colleague, Dr. Shin-Young Na, have now taken a closer look at this process and have made a surprising discovery. This is reported in the latest issue of the journal Immunity. They found that the brain itself allows the T cells to attack the myelin sheath under specific conditions – because by doing so it may be able to prevent greater damage to the sufferer.

Even though the findings from the brains of deceased MS patients point to a strong involvement by killer T cells, scientists have always had a problem with this: “In animal experiments, which are unavoidable for the development of new treatment strategies, there has been no convincing demonstration of an attack on the nerve sheaths that is mediated by killer T cells,” explains Hünig. For this reason, the research group made their search a little more complicated.

They infected mice in the laboratory with a specific species of bacteria – listeria –, which shares a protein with oligodendrocytes, and observed the consequences when peripheral parts of the body were infected and when the infection was confined to the brain.

The brain decides

The outcome: “With an infection in the periphery, the killer cells search for the pathogen all over the body, including the brain,” says Hünig. However, in this case the immune system is able to identify those killer cells that mistake the myelin sheaths for something alien because they recognize the protein the sheaths share with listeria and so attack. It fights the killer cells and destroys them. It is a different story when the infection is in the brain itself: “Then the attack is allowed, which destroys the protective myelin sheath and leads to the formation of the plaques you see with multiple sclerosis,” explains the scientist.

A kind of “trade-off” seems to be responsible for the difference in progression. The brain’s “decision” to allow the attack helps combat the pathogen. It would appear that the brain is applying the motto: better that a few infected cells are destroyed and nerve cell extensions are demyelized than that the pathogen spreads and may therefore kill the sufferer. However, in the absence of an infection with menacing pathogens, the brain “recognizes” that this is a misguided attack by killer T cells and destroys them. It is possible, though, that the brain may sometimes “overestimate” the threat posed by a microbial pathogen and may sacrifice the protective myelin sheath unnecessarily.

Next steps

“These findings could form the basis for future therapies focused on combating microbial pathogens in the brain as well as reducing the local inflammation they cause,” hopes Hünig. Since many researchers are convinced that viruses can trigger certain forms of multiple sclerosis, he believes it makes sense to continue to conduct research in this direction.

Oligodendrocytes Enforce Immune Tolerance of the Uninfected Brain by Purging the Peripheral Repertoire of Autoreactive CD8+ T Cells; Shin-Young Na, Andreas Hermann, Monica Sanchez-Ruiz, Alexander Storch, Martina Deckert and Thomas Hünig; Immunity, Published online: June 7, DOI: 10.1016/j.immuni.2012.04.009

Contact
Prof. Dr. Thomas Hünig, Department of Immunology, T: +49 (0)931 201-49951, e-mail: huenig@vim.uni-wuerzburg.de

Gunnar Bartsch | idw
Further information:
http://www.uni-wuerzburg.de

Further reports about: T cells immune system immunity killer T cells multiple sclerosis nerve cell

More articles from Health and Medicine:

nachricht Usher syndrome: Gene therapy restores hearing and balance
25.09.2017 | Institut Pasteur

nachricht MRI contrast agent locates and distinguishes aggressive from slow-growing breast cancer
25.09.2017 | Case Western Reserve University

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: The fastest light-driven current source

Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.

Graphene is up to the job

Im Focus: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Nerves control the body’s bacterial community

26.09.2017 | Life Sciences

Four elements make 2-D optical platform

26.09.2017 | Physics and Astronomy

Goodbye, login. Hello, heart scan

26.09.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>