Navigation Links
Immune exhaustion driven by antigen in chronic viral infection
Date:5/13/2009

A main reason why viruses such as HIV or hepatitis C persist despite a vigorous initial immune response is exhaustion. The T cells, or white blood cells, fighting a chronic infection eventually wear out.

Researchers at Emory Vaccine Center have demonstrated that exhaustion is driven by how the immune system detects infecting viruses.

To recognize the presence of a viral infection, T cells must be presented with bits of viral protein in a molecular frame supplied by other cells in the body -- called MHC (major histocompatibility complex) class I molecules.

In mice infected by lymphocytic choriomeningitis virus (LCMV), T cells became more or less exhausted depending on how much properly framed viral protein was available.

Insights from the research could guide efforts to revive the immune system in people with chronic viral infections. The results are published online this week in the Proceedings of the National Academy of Sciences.

Working with Vaccine Center director Rafi Ahmed, PhD, postdoctoral fellow Scott Mueller, PhD, examined the effects of limiting what kind of cells could display the viral antigens.

Ahmed is professor of microbiology and immunology at Emory University School of Medicine and a Georgia Research Alliance Eminent Scholar.

By performing bone marrow transplants on genetically engineered mice, Mueller created mice with MHC class I molecules on blood and immune system cells but missing from other cells such as nerve cells and connective tissue. LCMV infects both cells that come from bone marrow and cells that don't. But the roles each type of cell plays in communicating the infection to the immune system is different.

"We were trying to sort out which of several factors contribute to T cell exhaustion, such as viral antigen, inflammation and where the immune system encounters the virus," Mueller says. "What came out of these experiments allowed us to answer a broad question: the role of antigen in driving exhaustion."

When injected with LCMV, the altered mice had more energetic and responsive T cells early during the infection. But later, the altered mice had much higher levels of virus and more exhausted T cells. This contrast demonstrates how the level of antigen present is the motor behind immune exhaustion during the chronic infection.

"Early on, the T cells were healthier because they saw less antigen, and only saw it on cells that came from bone marrow," Mueller says. "But later, the immune system had trouble getting rid of the virus because the T cells couldn't recognize infection in cells that were not able to present the viral antigens."


'/>"/>

Contact: Holly Korschun
hkorsch@emory.edu
404-727-3990
Emory University
Source:Eurekalert

Related medicine news :

1. Penn study finds pro-death proteins required to regulate healthy immune function
2. Immune deficiency linked to a type of eye cancer
3. Tumors use enzyme to recruit regulatory T-cells and suppress immune response
4. Melanoma drug revs immune cells but cancer cells ignore it
5. Study identifies key player in the bodys immune response to chronic stress
6. MedImmune Resolves FDA Observations Regarding Manufacturing Process for FluMist(R)
7. UVA researchers find important clue to immune infertility
8. M.D. Anderson-led team reports possible key to autoimmune disease
9. Their immune cells, fighting your cancer
10. MedImmune Licenses Reverse Genetics Technology to GlaxoSmithKline for Use in Influenza Vaccine Development and Production
11. Occupational exposures may be linked to death from autoimmune disease
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... ... June 26, 2016 , ... Many women are confused ... endometriosis. These women need a treatment plan to not only alleviate symptoms and ... help for preservation of fertility and ultimately achieving a pregnancy. The specialists at ...
(Date:6/25/2016)... California (PRWEB) , ... June 25, 2016 , ... "With ... fit their specific project," said Christina Austin - CEO of Pixel Film Studios. ... customizable and all within Final Cut Pro X . Simply select a ProHand ...
(Date:6/25/2016)... ... ... On Friday, June 10, Van Mitchell, Secretary of the Maryland Department of Health ... of their exemplary accomplishments in worksite health promotion. , The Wellness at Work Awards ... at the BWI Marriott in Linthicum Heights. iHire was one of 42 businesses to ...
(Date:6/24/2016)... ... ... June 19, 2016 is World Sickle Cell Observance Day. In an effort ... holistic treatments, Serenity Recovery Center of Marne, Michigan, has issued a pain ... Disease (SCD) is a disorder of the red blood cells, which can cause episodes ...
(Date:6/24/2016)... ... June 24, 2016 , ... Dr. Amanda Cheng, ... treatment. Dr. Cheng has extensive experience with all areas of orthodontics, including robotic ... osteogenic orthodontics. , Micro-osteoperforation is a revolutionary adjunct to orthodontic treatment. It ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... June 23, 2016 Any dentist who has made ... the current process. Many of them do not even offer ... difficulties and high laboratory costs involved. And those who ARE ... at such a high cost that the majority of today,s ... Dr. Parsa Zadeh , founder of Dental Evolutions Inc. ...
(Date:6/23/2016)... , June 23, 2016 Roche (SIX: ... 510(k) clearance for its Elecsys BRAHMS PCT (procalcitonin) assay ... sepsis or septic shock. With this clearance, Roche is ... a fully integrated solution for sepsis risk assessment and ... with bacterial infection and PCT levels in blood can ...
(Date:6/23/2016)... -- Research and Markets has announced the addition ... to their offering. The ... commercial environment for MedImmune to enter. The US ageing population ... to drive considerable growth for effective anti-influenza medications. The introduction ... considerably, but development is still in its infancy. ...
Breaking Medicine Technology: