Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Keeping viruses at bay

12.08.2014

Our immunosensory system detects virus such as influenza via specific characteristics of viral ribonucleic acid.

Previously, it was unclear how the immune system prevents viruses from simply donning molecular camouflage in order to escape detection. An international team of researchers from the University of Bonn Hospital and the London Research Institute have now discovered that our immunosensory system attacks viruses on a molecular level. In this way, a healthy organism can keep rotaviruses, a common cause of diarrheal epidemics, at bay. The results have been published in the renowned journal "Nature".


Marion Goldeck, Dr. Martin Schlee (sitting), Dr. Winfried Barchet, Thomas Zillinger and Prof. Dr. med. Gunther Hartmann, Director of the Institute of Clinical Chemistry and Clinical Pharmacology.

(c) Photo: Claudia Siebenhüner/UKB

Every day our bodies are confronted with a variety of viruses and other pathogens. Our immune systems must constantly decide what is "foreign" and what is part of the body itself so that the body's own cells are not inadvertently attacked by its own defense troops. Viruses imitate the body's own structures and thus represent a special challenge for the immune system.

In this way, the immune system works like a sensory organ which continuously detects dangers and initiates the appropriate defense mechanisms. This immunosensory system searches for viruses by surveilling the body's own ribonucleic acid (RNA) for RNA with characteristics typical of viruses. In RNA viruses, RNA is the carrier of the virus's genetic information. To reproduce, viruses must multiply their RNA, and this multiplication leads to the development of molecular patterns which are in turn used to detect the viruses themselves.

It has been known for some time that RIG-I-like receptors (RLRs) play a crucial role in the detection of RNA viruses. These receptors act as “fire alarms” within the immune system: When RNA molecules from viruses bind to these receptors, a signal chain is initiated that leads to the production of substances that can ultimately combat the viruses.

"During amplification of viral RNA, a so-called triphosphate group, consisting of three phosphates, inevitably develops at one end of the newly formed RNA. A few years ago, we were the first to show that it is this triphosphate group which allows RIG-I to detect newly formed viral RNA. Previously, it was believed that viruses can elude this detection via simple deceptive molecular maneuvers," said Prof. Gunther Hartmann, Director of the Institute of Clinical Chemistry and Clinical Pharmacology of the University of Bonn Hospital.

RIG-I: A molecular attack against viruses

Together with scientists from the Immunobiology Laboratory of the London Research Institute in England, the scientists working with Dr. Martin Schlee and Prof. Dr. Gunther Hartmann at the University of Bonn Hospital investigated the immunorecognition of reoviruses. This family includes rotaviruses, which cause serious diarrheal illness and are responsible for the deaths of more than a million children worldwide every year.

The immunorecognition of reoviruses was previously unclear since their RNA does not contain a triphosphate group. Now the researchers discovered that, surprisingly, an RNA structure with two phosphates at the end of the RNA double-strand in reoviruses can likewise trigger RIG-I and alarm the immune system.

"This finding has significance for the detection of RNA viruses that extends far beyond reoviruses: It is comparatively simple for a virus to molecularly change the triphosphate in the course of its development,” said Dr. Schlee. The first step in this process is generally to split off the outermost phosphate of the triphosphate group, which leads to a diphosphate. This step is necessary for the virus to perform further modifications to its RNA and thus don a molecular cloak of invisibility.

However, any form of further molecular camouflage is made extremely difficult for the virus due to the additional highly specialized RIG-I-mediated immunorecognition of the diphosphate. Thus, RIG-I attacks the virus on both fronts, significantly restricting its further development.

"Without the investigation into reoviruses, we would not have discovered this universal mechanism of virus detection," said Prof. Hartmann. Since members of the reovirus family also contain a diphosphate group in their viral RNA, a healthy organism can also detect these viruses and curb these illnesses within a few days. However, malnourished children cannot summon these reserves, and the illness can become life-threatening.

The immune system: a sensory system for health

The researchers see a major application potential in the decoding of virus detection: "We are already currently developing artificially produced copies of viral RNA in order to alert our immune system to viruses in a targeted fashion," said Prof. Hartmann who is also director of the project "Novel Anti-infective Agents" at the German Centre for Infection Research (DZIF). Prof Hartmann is also currently speaker of the Cluster of Excellence ImmunoSensation, which is supported by a 28-million Euro grant from the German Research Foundation (DFG). The Cluster brings together experts from a variety of disciplines at the site and connects them to international research structures.

Publication: Antiviral immunity via RIG-I-mediated recognition of RNA bearing 5’diphosphates, “Nature”, DOI: 10.1038/nature13590

Contact information:

Prof. Dr. med. Gunther Hartmann
Director of the Institute of Clinical Chemistry
and Clinical Pharmacology
of the University of Bonn Hospital
Tel. 0228/28716080
E-Mail: Gunther.Hartmann@ukb.uni-bonn.de

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de

Further reports about: DFG Friedrich-Wilhelms-Universität RIG-I RNA healthy illness modifications structures

More articles from Life Sciences:

nachricht Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System

nachricht Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>