Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

USC researchers uncover mechanism that allows influenza virus to evade the body's immune response

25.05.2009
Findings could lead to new drug therapies to enhance innate immunity
Researchers at the University of Southern California (USC) have identified a critical molecular mechanism that allows the influenza virus to evade the body's immune response system.

The study will be published in the May 21 issue of the journal Cell Host & Microbe.

"We have found a mechanism that the influenza virus uses to inhibit the body's immune response that emphasizes the vital role of a certain protein in defending against viruses,"," says Jae Jung, Ph.D., professor and chair of the Department of Molecular Microbiology and Immunology at the Keck School of Medicine of USC, and the principal investigator of the study. "Along with our previous studies (Nature 2007 and PNAS 2008), this finding could provide researchers with the information needed to create a new drug to enhance immunity and block influenza virus infection and replication."

Several specific intracellular receptors are responsible for detecting the virus and activating the body's defensive mechanisms. When a virus' RNA enters the intracellular fluid, a receptor known as retinoic-acid-inducible gene I (RIG-I) detects it and triggers a response that limits virus replication and calls the body's defenses into action. RIG-I acts as the sensor and security force against attacks, Jung explains. Then, a protein known as TRIM25 helps RIG-I transmit an alarm signal, which ultimately floods the cell and surrounding tissue with antiviral interferons.

The influenza virus is highly infectious and poses a serious and sometimes deadly health risk because of its ability to mutate into new strains and spread quickly during seasonal epidemics, as seen in the recent outbreak of the H1N1 swine flu virus, Jung says.

Researchers have long been working to understand how respiratory influenza is able to slip past the body's innate immune responses. They have found that the influenza A virus has evolved by incorporating Non-structural protein 1 (NS1) into its genome to escape the RIG-I alarm system.

This process is one reason why the virus kills an average of 36,000 people every year. In fact, the 1918 "Spanish flu" pandemic influenza virus, which killed over 40 million people worldwide, muted the RIG-I response and interferon activity much more efficiently than contemporary flu viruses, Jung notes.

"Despite the conceptual linking of RIG-I with flu virus NS1, however, the precise mechanism has been unclear for a long period of time," he says.

By studying the immune responses of animal models, researchers found that the influenza A virus NS1 attacks TRIM25, inhibiting its ability to assist RIG-I trigger the alarm system against the virus. Remarkably, a flu virus carrying an NS1 mutant defective for this activity loses its virulence in animal models, Jung says.

"We now know that the influenza virus escapes recognition via the interaction of NS1 with TRIM25, which inhibits the body's immune response," he says. "Understanding this host-virus interaction is an essential step in developing safe and effective drugs to target the influenza virus."

This work was performed in collaboration with Adolfo Garcia-Sastre, Ph.D., at Mt. Sinai Medical School and the final doctorate experiments of Michaela Gack, Ph.D., who is the paper's first author and currently a faculty member at Harvard Medical School.

Michaela Ulrike Gack, Randy Allen Albrecht, Tomohiko Urano, Kyung-Soo Inn, I-Chueh Huang, Elena Carnero, Michael Farzan, Satoshi Inoue, Jae Ung Jung*, Adolfo Garica-Sastre*. "Influenza A Virus NS1 Targets the Ubiquitin Ligase TRIM25 to Evade Recognition by the Host VIral RNA Sensor RIG-I." Cell Host & Microbe. DOI: 10.1016/j.chom.2009.04.006.

Meghan Lewit | EurekAlert!
Further information:
http://www.usc.edu

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 >>>