Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Human against virus – a molecular race

14.12.2012
Immunologists discover a novel target to suppress a common virus

Most people become infected with the human cytomegalovirus (CMV) at some point in life. Over millions of years, our immune system has evolved a trick or two to defend us against this virus, but unfortunately, CMV evolved its own tricks, too. New drugs to target viral genes that counter the immune response might support the immune system in the fight against this widespread virus.


Macrophages release a signal that induces cellular suicide in virus-infected cells.
Manfred Rohde/HZI

The idea was born at the Helmholtz Centre for Infection Research (HZI), where scientists recently defined how CMV keeps infected cells alive, although they should undergo programmed suicide and simultaneously kill off the viruses that grow in them.

While the majority of us are life-long carriers of the herpes virus CMV, the infection is in balance with the immune system and remains asymptomatic in most of us. If the immune system becomes deficient, as is the case in organ transplanted people, or in those with AIDS, CMV can quickly become a serious problem. HZI researchers, along with their colleagues at the Max von Pettenkofer Institute in Munich, have now characterized a novel way in which even the body of severely immunodeficient people may defend itself against the virus. The researchers published their findings in the scientific journal PLOS Pathogens.

It is known that the immune system prompts infected cells to undergo self-destruction. In a process called apoptosis, these cells practically commit suicide. By sacrificing infected cells at an early stage, the body prevents pathogen spreading. The trigger may come from within the cell itself or from neighboring immune cells. HZI immunologists focused on the latter scenario, in which cells receive the suicide signal via "death receptors" on their surfaces. "We have managed to identify the immune cells that send out the signaling molecules, which dock on death receptors," says HZI scientist Dr. Linda Ebermann. This "death signal" originates from macrophages, the immune system's scavenger cells that engulf invading pathogens. Activated macrophages migrate to places of inflammation where virus-infected cells abound. There, they release bioactive molecules, which induce suicide in surrounding cells. Up to now, it was unknown that macrophages contribute to virus control in this way.

Not only did the HZI immunologists identify the source of the signals. They also demonstrated what the viruses' evolutionary response in the molecular arms race with the host looks like. "Viruses are not alive. To replicate, they need a living host cell," Ebermann explains. "Cytomegalovirus forces infected cells to manufacture proteins from viral genes. One of those can suppress the cellular suicide program. That way, the virus can proliferate and spread undisturbed."

In their study, the researchers took advantage of a CMV variant that specifically infects mice. This strain closely resembles the one that infects humans: just as people with a weakened immune system would fall ill if infected with CMV, the murine CMV causes disease in immunocompromised mice, which lack certain components of their immune system. In these mice, the virus successfully shuts down the cellular suicide program with the help of a protein called M36 and thus ensures survival of its host cell. Remarkably, CMV mutants lacking this gene cannot replicate even in extremely susceptible mouse strains, where a single infectious unit of the wild-type virus would be lethal. Chances are that the human virus may work in the same way. "The proteins that inhibit apoptosis in human and in the mouse model are highly similar. Therefore we can pretty much assume that our findings can readily be applied to humans," explains Prof. Luka Cicin-Sain, head of HZI's Immune Aging and Chronic Infections research group, and assistant professor at the MHH's Institute of Virology.

For the time being, the virus has the upper hand in an immunocompromised person, but the HZI researchers' work has helped to uncover a viral protein which is critical for viral replication and therefore may be a valid target for antiviral drugs. According to Cicin-Sain, "it is conceivable that, with the help of drugs, we may be able to prevent CMV from shutting down the cellular suicide program. In that case, we would deprive the virus of the chance to spread, which would benefit CMV infected patients with an already compromised immune system."

Original publication:
Linda Ebermann, Zsolt Ruzsics, Carlos A. Guzmán, Nico van Rooijen, Rosaely Casalegno-Garduño, Ulrich Koszinowski, Luka Čičin-Šain
Block of Death-Receptor Apoptosis Protects Mouse Cytomegalovirus from Macrophages and is a Determinant of Virulence in Immunodeficient Hosts

PLOS Pathogens 2012

These findings are the first results of the Helmholtz Virtual Institute for Viral Strategies of Immune Evasion (VISTRIE), an international consortium of scientists working at Helmholtz institutes and leading German and international universities that was initiated by HZI scientists led by Prof. Luka Cicin-Sain.

The group "Immune Aging and Chronic Infections" investigates the influence of pathogens on the aging of the immune system. To do so, the researchers are studying infection with cytomegalovirus (CMV).

The Helmholtz Centre for Infection Research
At the Helmholtz Centre for Infection Research (HZI) in Braunschweig, scientists are studying microbial virulence factors, host-pathogen interactions and immunity. The goal is to develop strategies for the diagnosis, prevention and therapy of human infectious diseases.

http://www.helmholtz-hzi.de/en

Dr. Birgit Manno | Helmholtz-Zentrum
Further information:
http://www.helmholtz-hzi.de/en
http://www.helmholtz-hzi.de/en/news_events/news/view/article/complete/human_against_virus_a_molecular_race/

More articles from Life Sciences:

nachricht A cell senses its own curves: New research from the MBL Whitman Center
29.04.2016 | Marine Biological Laboratory

nachricht A New Discovery in the Fight against Cancer: Tumor Cells Switch to a Different Mode
29.04.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Tiny microbots that can clean up water

Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.

Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...

Im Focus: ORNL researchers discover new state of water molecule

Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.

In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...

Im Focus: Bionic Lightweight Design researchers of the Alfred Wegener Institute at Hannover Messe 2016

Honeycomb structures as the basic building block for industrial applications presented using holo pyramid

Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...

Im Focus: New world record for fullerene-free polymer solar cells

Polymer solar cells can be even cheaper and more reliable thanks to a breakthrough by scientists at Linköping University and the Chinese Academy of Sciences (CAS). This work is about avoiding costly and unstable fullerenes.

Polymer solar cells can be even cheaper and more reliable thanks to a breakthrough by scientists at Linköping University and the Chinese Academy of Sciences...

Im Focus: Ultra-thin glass is up and coming

As one of the leading R&D partners in the development of surface technologies and organic electronics, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP will be exhibiting its recent achievements in vacuum coating of ultra-thin glass at SVC TechCon 2016 (Booth 846), taking place in Indianapolis / USA from May 9 – 13.

Fraunhofer FEP is an experienced partner for technological developments, known for testing the limits of new materials and for optimization of those materials...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The “AC21 International Forum 2016” is About to Begin

27.04.2016 | Event News

Soft switching combines efficiency and improved electro-magnetic compatibility

15.04.2016 | Event News

Grid-Supportive Buildings Give Boost to Renewable Energy Integration

12.04.2016 | Event News

 
Latest News

Winds a quarter the speed of light spotted leaving mysterious binary systems

29.04.2016 | Physics and Astronomy

Fiber optic biosensor-integrated microfluidic chip to detect glucose levels

29.04.2016 | Health and Medicine

A cell senses its own curves: New research from the MBL Whitman Center

29.04.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>