Featured Research

from universities, journals, and other organizations

How the immune system responds to hepatitis A virus

Date:
June 21, 2011
Source:
Southwest Foundation for Biomedical Research
Summary:
A surprising finding in a study comparing hepatitis C virus (HCV) with hepatitis A virus (HAV) infections in chimpanzees sheds new light on the nature of the body's immune response to these viruses.

A surprising finding in a study comparing hepatitis C virus (HCV) with hepatitis A virus (HAV) infections in chimpanzees by a team that includes scientists from the Texas Biomedical Research Institute sheds new light on the nature of the body's immune response to these viruses.

Related Articles


Understanding how hepatitis C becomes chronic is very important because some 200 million people worldwide and 3.2 million people in the U.S. are chronically infected with HCV and are at risk for progression to cirrhosis and liver cancer. Hepatitis C associated liver disease is the most common indication for liver transplantation, while liver cancer due to HCV infection is now the most rapidly increasing cause of cancer death in the U.S.

"Remarkably, we found that HAV was more adept at evading the innate immune response than HCV, the virus that ultimately causes chronic infections," said Robert E. Lanford, Ph.D., a Texas Biomed virologist. The novel findings demonstrate that HAV is the stealthier virus when it comes to evading the innate immune response, despite the lack of persistent infections.

Hepatitis C infections are characterized by a failure of the immune system to combat and eliminate the virus. "We suspect this failure of the immune system shares attributes with other persistent viruses such as HIV and hepatitis B virus," said Lanford. By comparing two similar viruses that infect the liver, one that is always cleared by the immune system, HAV, and one that frequently evades the immune response, HCV, the team hoped to unravel the mystery of how HCV causes lifelong persistent infections.

The research team involved scientists from Texas Biomed in San Antonio, the University of North Carolina (UNC) at Chapel Hill, and Nationwide Children's Hospital in Columbus, Ohio. The study performed in chimpanzees at Texas Biomed's Southwest National Primate Research Center (SNPRC) and funded by the National Institutes of Health, is published June 20 in Proceedings of the National Academy of Sciences U.S.A.

The new study points out the critical need for more information about how the immune system reacts to HCV. It also reinforces the importance of chimpanzee research in this effort. The chimpanzee, the only animal model susceptible to HCV infection, was critical for probing the molecular differences in gene expression in the liver related to infection by the two viruses.

Examination of the adaptive immune system by co-author Christopher M. Walker, Ph.D., of Nationwide Children's Hospital in Columbus, Ohio, found that the T cell response to HAV was unique as well. "We expected the immune response to kill all HAV infected cells in a short time frame, and yet we could detect the genome of the virus in the liver for up to one year, long after symptoms of the disease were resolved," Lanford explained.

"Hepatitis viruses have co-evolved with humans over a very long period of time and they are good at evading the immune system, but nobody understands how hepatitis C becomes a chronic infection," said co-author Stanley M. Lemon, M.D., of UNC.

"The surprising and exciting results of this research program further highlight the critical value of the chimpanzee model in research on hepatitis," said John L. VandeBerg, Ph.D., Texas Biomed's chief scientific officer and SNPRC director

Others on the study included Deborah Chavez, M.S., and Bernadette Guerra, B.S., of Texas Biomed; Kathleen Brasky, D.V.M, of SNPRC; Zongdi Feng, Ph.D., and Daisuke Yamane, D.V.M, Ph.D., of UNC; Yan Zhou, Ph.D., Nationwide Children's Hospital; and Alan S. Perelson, Ph.D., of the Los Alamos National Laboratory.


Story Source:

The above story is based on materials provided by Southwest Foundation for Biomedical Research. Note: Materials may be edited for content and length.


Journal Reference:

  1. Robert E. Lanford, Zongdi Feng, Deborah Chavez, Bernadette Guerra, Kathleen M. Brasky, Yan Zhou, Daisuke Yamane, Alan S. Perelson, Christopher M. Walker, and Stanley M. Lemon. Acute hepatitis A virus infection is associated with a limited type I interferon response and persistence of intrahepatic viral RNA. PNAS, June 20, 2011 DOI: 10.1073/pnas.1101939108

Cite This Page:

Southwest Foundation for Biomedical Research. "How the immune system responds to hepatitis A virus." ScienceDaily. ScienceDaily, 21 June 2011. <www.sciencedaily.com/releases/2011/06/110620161302.htm>.
Southwest Foundation for Biomedical Research. (2011, June 21). How the immune system responds to hepatitis A virus. ScienceDaily. Retrieved January 29, 2015 from www.sciencedaily.com/releases/2011/06/110620161302.htm
Southwest Foundation for Biomedical Research. "How the immune system responds to hepatitis A virus." ScienceDaily. www.sciencedaily.com/releases/2011/06/110620161302.htm (accessed January 29, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, January 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Malnutrition on the Rise as Violence Flares in C. Africa

Malnutrition on the Rise as Violence Flares in C. Africa

AFP (Jan. 28, 2015) Violence can flare up at any moment in Bambari with only a bridge separating Muslims and Christians. Malnutrition is on the rise and lack of water means simple cooking fires threaten to destroy makeshift camps where people are living. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
Poultry Culled in Taiwan to Thwart Bird Flu

Poultry Culled in Taiwan to Thwart Bird Flu

Reuters - News Video Online (Jan. 28, 2015) Taiwan culls over a million poultry in efforts to halt various strains of avian flu. Julie Noce reports. Video provided by Reuters
Powered by NewsLook.com
Media Criticizing Parents For Not Vaccinating Children

Media Criticizing Parents For Not Vaccinating Children

Newsy (Jan. 28, 2015) As the Disneyland measles outbreak continues to spread, the media says parents who choose not to vaccinate their children are part of the cause. Video provided by Newsy
Powered by NewsLook.com
Shark Bite Victim Making Amazing Recovery

Shark Bite Victim Making Amazing Recovery

AP (Jan. 27, 2015) A Texas woman who lost more than five pounds of flesh to a shark in the Bahamas earlier this month could be released from a Florida hospital soon. Experts believe she was bitten by a bull shark while snorkeling. (Jan. 27) Video provided by AP
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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