Viruses are microscopically sized parasites. They plant their genes in the cells of their victim in order to 'reprogram' them. The infected cells then no longer produce what they need to live, making lots of new viruses instead.
Luckily, in most cases this hostile takeover does not go unnoticed. This is ensured by the cells' own sensors that recognise alien genetic material. One of them is RIG-I. When RIG-I encounters virus genes, it ensures that the body releases interferon. The interferon then in turn puts killer cells on combat standby, which then destroy the infected cells.
Yet this is only part of the truth. 'According to our results RIG-I appears to play a far more prominent role in the defence against viruses than was previously thought,' Dr. Jürgen Ruland from the University Hospital Rechts der Isar at the Technical University of Munich explains. As a result, many virus infections are accompanied by a high temperature. That is also what happens with influenza, for example. This symptom cannot be explained by interferon release alone.
In most cases it is cytokines which trigger the fever. 'We have now been able to show, for the first time, that RIG-I also cranks up the production of a central cytokine in the case of a virus infection,' Dr. Hendrik Poeck explains. He and his colleagues Dr. Michael Bscheider and Dr. Olaf Groß are the primary authors of the study. This is a reference to interleukin 1, probably the most important cytokine known today.
Do cytokines cause more severe courses of a disease?
When RIG-I comes into contact with a virus gene, it does two things. On the one hand, it ensures that certain immune cells produce pro-interleukin, the precursor of interleukin 1, en masse. At the same time it activates an enzyme via a complicated signalling pathway which transforms pro-interleukin into interleukin 1. 'This interleukin 1 then ensures that the typical symptoms of a virus infection such as fever or shivering occur,' Professor Veit Hornung from the Bonn University Clinic explains.
As yet the researchers do not know how important this newly discovered immune mechanism is for the successful defence against the virus. The release of interleukin may also have negative consequences. 'There is the hypothesis that an overproduction of cytokines may lead to extremely severe courses of virus diseases,' Professor Gunther Hartmann says. Medicines that prevent such a 'cytokine storm' may therefore alleviate the progress of the disease.
Recognition of RNA virus by RIG-I results in activation of CARD9 and inflammasome signaling for interleukin 1beta production. Hendrik Poeck, Michael Bscheider, Olaf Gross, Katrin Finger, Susanne Roth, Manuele Rebsamen, Nicole Hannesschläger, Martin Schlee, Simon Rothenfusser, Winfried Barchet, Hiroki Kato, Shizuo Akira, Satoshi Inoue, Stefan Endres, Christian Peschel, Gunther Hartmann, Veit Hornung & Jürgen Ruland. Nature Immunology, doi: 10.1038/ni.1824Contact:
Veit Hornung | EurekAlert!
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester
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,...
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...
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...
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...
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...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences