Featured Research

from universities, journals, and other organizations

Influenza Virus Evades Body's Immune Response Through Newly Discovered Mechanism

Date:
May 21, 2009
Source:
University of Southern California
Summary:
Researchers have identified a critical molecular mechanism that allows the influenza virus to evade the body's immune response system.

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.

"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.


Story Source:

The above story is based on materials provided by University of Southern California. Note: Materials may be edited for content and length.


Journal Reference:

  1. 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, May 21, 2009 DOI: 10.1016/j.chom.2009.04.006

Cite This Page:

University of Southern California. "Influenza Virus Evades Body's Immune Response Through Newly Discovered Mechanism." ScienceDaily. ScienceDaily, 21 May 2009. <www.sciencedaily.com/releases/2009/05/090520181105.htm>.
University of Southern California. (2009, May 21). Influenza Virus Evades Body's Immune Response Through Newly Discovered Mechanism. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2009/05/090520181105.htm
University of Southern California. "Influenza Virus Evades Body's Immune Response Through Newly Discovered Mechanism." ScienceDaily. www.sciencedaily.com/releases/2009/05/090520181105.htm (accessed July 23, 2014).

Share This




More Health & Medicine News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Courts Conflicted Over Healthcare Law

Courts Conflicted Over Healthcare Law

AP (July 22, 2014) Two federal appeals courts issued conflicting rulings Tuesday on the legality of the federally-run healthcare exchange that operates in 36 states. (July 22) Video provided by AP
Powered by NewsLook.com
Why Do People Believe We Only Use 10 Percent Of Our Brains?

Why Do People Believe We Only Use 10 Percent Of Our Brains?

Newsy (July 22, 2014) The new sci-fi thriller "Lucy" is making people question whether we really use all our brainpower. But, as scientists have insisted for years, we do. Video provided by Newsy
Powered by NewsLook.com
Scientists Find New Way To Make Human Platelets

Scientists Find New Way To Make Human Platelets

Newsy (July 22, 2014) Boston scientists have discovered a new way to create fully functioning human platelets using a bioreactor and human stem cells. Video provided by Newsy
Powered by NewsLook.com
Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins