Featured Research

from universities, journals, and other organizations

Why the immune system fails to kill HIV

Date:
July 18, 2014
Source:
Karolinska Institutet
Summary:
Our immune system contains CD8+ T cells which protect us from various diseases such as cancer and viruses. Some of them are specifically tasked with killing cells infected with the HIV virus – and researchers have for the first time identified a key explanation for why these cells are unsuccessful in their task. In simple terms, the immune system's ignition keys have not been turned all the way to the start position, which would enable the CD8+ T cells to kill the cells infected with HIV.

Our immune system contains CD8+ T cells which protect us from various diseases such as cancer and viruses. Some of them are specifically tasked with killing cells infected with the HIV virus -- and researchers from Karolinska Institutet in Sweden, together with international colleagues, have for the first time identified a key explanation for why these cells are unsuccessful in their task. In simple terms, the immune system's ignition keys have not been turned all the way to the start position, which would enable the CD8+ T cells to kill the cells infected with HIV.

Related Articles


It has long been known that CD8+ T cells that are meant to target and kill the HIV virus lose important functions; they become exhausted and cannot complete their task. In one study, published in the journal PLOS Pathogens, researchers have successfully shown at the molecular level what it is that weakens these important CD8+ T cells.

There are two transcription factors that are particularly important to CD8+ T cells. They are called T-bet and Eomes and work as ignition keys for the machinery of the immune system -- they ensure that CD8+ T cells are correctly instructed to fight the specific disease. In simple terms, T-bet has the role of an instigator that induces CD8+ T cells to divide and mature. Eomes have a more regulatory role and are primarily active in building a memory against an infection that has completely healed, in order to be ready for a new episode of the infection.

Researchers have studied how T-bet and Eomes are expressed in a total of 64 HIV-infected people, the majority of whom were treated in the infection clinic at the Karolinska University Hospital and the sexual health clinic at the Stockholm South General Hospital. The study shows that the CD8+ T cells specifically targeting HIV-infected cells have a low expression of T-bet, but an increased expression of regulatory Eomes. This leads to CD8+ T cells that are maturing poorly and inhibit their ability to kill HIV-infected cells.

Unfortunately, this pattern of the transcription factors was present even when the participants' HIV was responding well to medication, in that the level of HIV virus sunk so low that it was not measurable in their blood.

"This probably explains why CD8+ T cells continue to function poorly despite long-term treatment with antiviral drugs. We have previously known this to be the case, though we have not known why," says Marcus Buggert, researcher at the Department of Laboratory Medicine at Karolinska Institutet.

The researchers hope to discover how the transcription factors' expression can be affected so that T-bet can be increased in patients with HIV. That would possibly give the immune system a chance of killing HIV-infected cells and thus making it easier to cure HIV infection.

"If we can get past this barrier and discover how to control the regulation of these transcription factors, this would open the door to creating a vaccine or cure for HIV. This could be one way of creating an effective immune response that is able to kill HIV-infected cells," says Annika Karlsson, senior research fellow in virology at the Department of Laboratory Medicine at Karolinska Institutet.


Story Source:

The above story is based on materials provided by Karolinska Institutet. Note: Materials may be edited for content and length.


Journal Reference:

  1. Marcus Buggert, Johanna Tauriainen, Takuya Yamamoto, Juliet Frederiksen, Martin A. Ivarsson, Jakob Michaëlsson, Ole Lund, Bo Hejdeman, Marianne Jansson, Anders Sönnerborg, Richard A. Koup, Michael R. Betts, Annika C. Karlsson. T-bet and Eomes Are Differentially Linked to the Exhausted Phenotype of CD8 T Cells in HIV Infection. PLoS Pathogens, 2014; 10 (7): e1004251 DOI: 10.1371/journal.ppat.1004251

Cite This Page:

Karolinska Institutet. "Why the immune system fails to kill HIV." ScienceDaily. ScienceDaily, 18 July 2014. <www.sciencedaily.com/releases/2014/07/140718095416.htm>.
Karolinska Institutet. (2014, July 18). Why the immune system fails to kill HIV. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/07/140718095416.htm
Karolinska Institutet. "Why the immune system fails to kill HIV." ScienceDaily. www.sciencedaily.com/releases/2014/07/140718095416.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Texas Nurse Nina Pham Cured of Ebola

Texas Nurse Nina Pham Cured of Ebola

AFP (Oct. 25, 2014) — An American nurse who contracted Ebola while caring for a Liberian patient in Texas has been declared free of the virus and will leave the hospital. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) — IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) — A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) — The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) 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