Navigation Links
'Pep talk' can revive immune cells exhausted by chronic viral infection

Chronic infections by viruses such as HIV or hepatitis C eventually take hold because they wear the immune system out, a phenomenon immunologists describe as exhaustion.

Yet exhausted immune cells can be revived after the introduction of fresh cells that act like coaches giving a pep talk, researchers at Emory Vaccine Center have found. Their findings provide support for an emerging strategy for treating chronic infections: infusing immune cells back into patients after a period of conditioning.

The results are published this week in Proceedings of the National Academy of Sciences Early Edition.

The first author of the paper is Rachael Aubert, a student in Emory's Immunology and Molecular Pathogenesis program who completed her doctorate in 2009. Senior author Rafi Ahmed, PhD, is director of the Emory Vaccine Center and a Georgia Research Alliance Eminent Scholar.

Ahmed's laboratory has extensive experience studying mice infected with lymphocytic choriomeningitis virus (LCMV). Immune responses against LCMV are driven by CD8 or "killer" T cells, which destroy virus-infected cells in the body. But a few weeks after exposure to LCMV, the mice develop a chronic infection that their immune systems cannot shake off, similar to when humans are infected by viruses like HIV and hepatitis C.

Aubert and her co-workers examined what happened to mice chronically infected with LCMV when they infused CD4 or "helper" T cells from uninfected mice. After the infusion, the CD8 cells in the infected mice revived and the levels of virus in their bodies decreased by a factor of four after a month. Like coaches encouraging a tired athlete, the helper cells drove the killer cells that were already in the infected mice to emerge from exhaustion and re-engage.

The cell-based treatment was especially effective when combined with an antibody that blocks the molecule PD-1, which appears on exhausted T cells and inhibits their functioning. The antibody against PD-1 helps the exhausted T cells to revive, and enhances the function of the helper cells as well: the combination reduced viral levels by roughly ten-fold, and made the virus undetectable in some mice.

"We have not seen this sharp of a reduction in viral levels in this system before," says co-author Alice Kamphorst, a postdoctoral fellow.

The helper cells were all genetically engineered to recognize LCMV, a difference between mouse experiments and potential clinical application. However, it may be possible to remove helper T cells from a human patient and stimulate them so that all the cells that recognize a given virus grow, Kamphorst says.

"This is an active area of research and several laboratories are looking at how best to stimulate T cells and re-introduce them," she says.

In addition, she and her co-workers are examining what types of hormones or signaling molecules the helper cells provide the killer cells. That way, that molecule could be provided directly, instead of cell therapy, she says.

The molecule PD-1 was previously identified by Ahmed and colleagues as a target for therapy designed to re-activate exhausted immune cells. Antibodies against PD-1 have been undergoing tests in clinical studies against hepatitis C and several forms of cancer.


Contact: Holly Korschun
Emory University

Related medicine news :

1. Dr. Luther T. Clark to present Merck Academy Talk at SUNY Downstate
2. Talking About Size, Shape May Aid Math Skills
3. Law barring doctors talking to patients about gun ownership undermines public health issue
4. With Rude Workers, Customers Walk but Dont Talk
5. Talking -- or Not Talking -- Can Give Cancer Patients a Sense of Control
6. Rules Help When Talking About Infertility
7. High-risk stroke patients more likely to get follow-up care after motivational talk
8. Spiritual Talks May Boost Patients View of Hospital Care
9. Special Talk Therapy Seems to Help Dying Patients
10. Talking to Teens May Help Them Cut Back on Pot Smoking
11. Tots Who Are Late Talkers Typically Turn Out Fine: Study
Post Your Comments:
(Date:11/26/2015)... ... November 26, 2015 , ... Inevitably when people think ... customers choose to buy during the Black Friday and Cyber Monday massage chair ... to search the Internet high and low to find the best massage chair deals, ...
(Date:11/26/2015)... ... November 26, 2015 , ... Somu Sivaramakrishnan announced ... franchise owner, Somu now offers travelers, value and care based Travel Services, including ... sales, as well as, cabin upgrades and special amenities such as, shore excursions, ...
(Date:11/26/2015)... ... 2015 , ... Jobs in hospital medical laboratories and in the imaging field ... agency Aureus Medical Group . These fields, as well as travel ... for healthcare jobs through the company’s website, , The leading healthcare ...
(Date:11/26/2015)... BOSTON, Mass. (PRWEB) , ... November 26, 2015 ... ... a thorough second medical opinion process, participated in the 61st annual Employee Benefits ... Benefit Plans and took place Sunday, November 8th through Wednesday, November 11th, 2015. ...
(Date:11/26/2015)... ... November 26, 2015 , ... ... health and wellness consultation, has collaborated with Women’s Web – an online ... queries on topics on mental and emotional well-being relationship, life balance, stress, ...
Breaking Medicine News(10 mins):
(Date:11/27/2015)... 27, 2015 --> ... go online. The potential to save costs, improve treatment ... far from fully exploited as yet. Here, particular emphasis ... either via mobile tablet or directly at the patients, ... ) -->      (Photo: ...
(Date:11/27/2015)... 27, 2015  Lannett Company, Inc. (NYSE: ... the acquisition of Kremers Urban Pharmaceuticals Inc. (KU), ... biopharmaceuticals company UCB S.A. (Euronext: UCB). ... acquired KU from UCB for total consideration of ... a customary working capital adjustment, a deduction of ...
(Date:11/27/2015)... 2015 ... "2016 Global Tumor Marker Testing Market: ... Sales Segment Forecasts, Innovative Technologies, Instrumentation Review, ... their offering. --> ) ... "2016 Global Tumor Marker Testing Market: Supplier ...
Breaking Medicine Technology: