Featured Research

from universities, journals, and other organizations

Immune Cell Communication Key To Hunting Viruses

Date:
October 26, 2006
Source:
Thomas Jefferson University
Summary:
Immunologists have used nanotechnology to create a novel "biosensor" to solve in part a perplexing problem in immunology: how the immune system's killer T-cells hunt down invading viruses. They have found that surprisingly little virus can turn on killer T-cells, thanks to some complicated communication among "antigen presenting" proteins that recognize and attach to the virus, making it visible to the immune system. Presenting proteins cooperate, spreading a signal among receptors and boosting T-cell response.

Immunologists at the Kimmel Cancer Center at Thomas Jefferson University in Philadelphia have used nanotechnology to create a novel “biosensor” to solve in part a perplexing problem in immunology: how immune system cells called killer T-cells hunt down invading viruses.

They found that surprisingly little virus can turn on the killer T-cells, thanks to some complicated communication among so-called “antigen presenting” proteins that recognize and attach to the virus, in turn, making it visible to the immune system. T-cell receptors then “see” the virus, activating the T-cells.

The researchers, led by Yuri Sykulev, M.D., Ph.D., associate professor of microbiology and immunology at Jefferson Medical College of Thomas Jefferson University, showed that different types of presenting proteins cooperate, spreading a signal among only a few T-cell receptors and boosting the T-cell response. This helps explain how only a few virus-infected cells can cause a killer T-cell response. They report their findings this week in an online edition of the Proceedings of the National Academy of Sciences.

Understanding how the immune system responds to viral threats, says Dr. Sykulev, is critical to finding better ways to manipulate it and could have implications for improved vaccine development.

To better understand how proteins are recognized by killer T-cells, Dr. Sykulev and his co-workers created a biosensor out of semiconductor nanoparticles called quantum dots. These served as a unique scaffold to carry presenting proteins (called Major Histocompatibility Complex (MHC) proteins) and the attached virus portion, mimicking the clustering of MHC proteins on the surface of target cells. The researchers were able to place many MHC complexes, both with virus and non-virus fragments, and compared what was recognized by specific T-cell receptors on killer T-cells.

What they found surprised them. While the nanoparticle specifically bound to the surface of T-cells with receptors recognizing the viral-MHC complex, the control – a biosensor that carried the same MHC protein with a different peptide not recognized by the T-cells – unexpectedly also binded almost as strongly. “When we have such an arrangement of MHC proteins, we were able to see something no one had seen before – a very strong contribution of non-viral peptide-MHC interaction with a co-receptor,” he says. “Such cooperativity we think can be achieved when MHC complexes are close to each other.

“We’ve shown that when we try to mimic the positioning of MHC protein on quantum dots, which we believe is similar to what it is on the cell membrane, we have this very strong binding. An important message is that a single virus-MHC complex recognized in the context of self-MHC complexes is sufficient to activate a T-cell response, which is amazing,” he says. “That’s the power of killer cells.

“We always suspected that recognition of other peptide MHCs, like self-peptide MHCs derived from normal proteins, could facilitate recognition, but it was not clear until now how this happened.” Dr. Sykulev notes that this finding is not only relevant to viral infected cells, but to tumor cells as well. Both usually express very low levels of proteins that killer cells recognize.


Story Source:

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


Cite This Page:

Thomas Jefferson University. "Immune Cell Communication Key To Hunting Viruses." ScienceDaily. ScienceDaily, 26 October 2006. <www.sciencedaily.com/releases/2006/10/061025170034.htm>.
Thomas Jefferson University. (2006, October 26). Immune Cell Communication Key To Hunting Viruses. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2006/10/061025170034.htm
Thomas Jefferson University. "Immune Cell Communication Key To Hunting Viruses." ScienceDaily. www.sciencedaily.com/releases/2006/10/061025170034.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) 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:
from the past week

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