Navigation Links
Study details hepatitis C ability to block immune system response

The study was published in an advance online edition of the Proceedings of the National Academy of Sciences on May 17.

Hepatitis C virus (HCV) is a worldwide public health problem. The World Health Organization estimates that 170 million people worldwide are chronically infected and that between 3-4 million are newly infected annually. HCV is the leading cause of chronic liver disease including hepatic fibrosis, end-stage cirrhosis, and hepatocellular carcinoma. There is no vaccine available to prevent HCV, and current therapies are costly, have serious side effects and are curative in only a fraction of patients. According to the World Health Organization, the major causes of HCV infection are use of unscreened blood transfusions, and re-use of needles and syringes that have not been adequately sterilized.

Viral infections like hepatitis C often trigger an immediate innate immune response involving release of type 1 interferon (IFN-? and IFN-?). In turn, type 1 interferon stimulates the production of a family of what are known as IFN stimulated genes that have a multitude of inhibitory effects on viral replication in infected and neighboring uninfected cells. While interferon production and other immune responses can greatly influence the course of a number of different viral infections, many human pathogenic viruses have evolved distinct strategies to inhibit the early signaling events leading to interferon production. HCV is no different.

"We have previously demonstrated that many interferon stimulated genes with antiviral activity are induced in the liver during HCV infection," said Francis V. Chisari, M.D., a Scripps Research professor whose laboratory conducted the study. "Despite their induction, the virus can persist indefinitely, indicating that it is resistant to their antiviral effects."

The current study sheds light on one strategy the hepatitis C virus uses to resist the immune system. The findings suggest that the hepat itis C virus inhibits the activity of naturally occurring interferon by shutting down a key antiviral signaling protein.

Early after HCV infection, the immune system responds to viral RNA by activating a signaling cascade in the infected cells that results in the production of type 1 interferon. One of the intermediaries in that cascade is a mitochondrial antiviral signaling protein (MAVS). HCV blocks the production of type1 interferon by using its protease activity to destroy MAVS. By preventing infected cells from producing interferon, the virus inhibits the body's immune response against HCV, enabling it to persist.

"Our new work shows that HCV does not induce interferon-? or antiviral interferon stimulated genes in the infected cells," Chisari said. "This means that the antiviral interferon stimulated genes expressed in the HCV-infected liver are likely produced by uninfected cells in some novel fashion and that the virus has other tricks up its sleeve that makes it resistant to their antiviral effects. Further study is needed to understand which cells in the liver produce the interferon and how the virus can resist the broad spectrum of these antiviral effects."

The knowledge gained from fundamental studies such as these could lay the groundwork for the development of potential new treatment strategies for this devastating global disease.


'"/>

Source:Scripps Research Institute


Related biology news :

1. Novel Asthma Study Shows Multiple Genetic Input Required; Single-gene Solution Shot Down
2. Emory Study Tests Bone Marrow Stem Cells to Improve Circulation in Legs
3. UCLA Study Shows One-Third of Drug Ads in Medical Journals Do Not Contain References Supporting Medical Claims
4. Study Demonstrates Gene Expression Microarrays are Comparable and Reproducible
5. Study Links Ebola Outbreaks To Animal Carcasses
6. Breakthrough Microarray-based Technology for the Study of Cancer
7. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
8. Study finds more than one-third of human genome regulated by RNA
9. Leukemia Drug Breakthrough Study In New England Journal Of Medicine
10. Study identifies predictors of HIV drug resistance in patients beginning triple therapy
11. New Study from Affymetrix Laboratories Points to Changing View of How Genome Works
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:3/10/2016)... Pa. , March 10, 2016   Unisys Corporation ... Customs and Border Protection (CBP) is testing its biometric ... San Diego to help identify certain non-U.S. ... . The test, designed to help determine the efficiency ... environment, began in February and will run until May 2016. ...
(Date:3/3/2016)... -- FlexTech, a SEMI Strategic Association Partner, awarded five FLEXI ... Leadership in Education, and, in a category new this ... year of the FLEXI Awards and the winners join ... past years . Judging was done on a set ... by a panel of non-affiliated, independent, industry experts. ...
(Date:3/1/2016)... March 1, 2016 ... addition of the  "Global Biometric Access ... to their offering. --> ... of the  "Global Biometric Access Control ... their offering. --> Research ...
Breaking Biology News(10 mins):
(Date:4/27/2016)... ... April 27, 2016 , ... Cambridge Semantics, the leading ... today announced that it has been named to The Silicon Review’s “20 Fastest Growing ... other markets, Cambridge Semantics serves the needs of end users facing some of the ...
(Date:4/27/2016)... , April 27, 2016 ... (CSE: NSK) (OTCPink: NSKQB) ( Frankfurt ... an ihre Pressemitteilung vom 13. August 2015 die ... ihre Finanzen um zusätzliche 200.000.000 Einheiten auf 400.000.000 ... Dollar zu bringen. Davon wurden 157.900.000 Einheiten mit ...
(Date:4/27/2016)... ... April 27, 2016 , ... ... to its Scientific Advisory Board. Dr. Lamka will assist PathSensors in expanding the ... , PathSensors deploys the CANARY® test platform for the detection of harmful ...
(Date:4/27/2016)... , April 27, 2016 MedDay, ... disorders, today announces the appointment of Catherine Moukheibir as Chairman ... MedDay,s previous Chairman, Jean Jacques Garaud , who contributed ... change is effective immediately. Catherine started her career ... and London .  She held ...
Breaking Biology Technology: