Featured Research

from universities, journals, and other organizations

Natural Born Killers: How The Body's Frontline Immune Cells Decide Which Cells To Destroy

Date:
July 31, 2009
Source:
Imperial College London
Summary:
The mechanism used by "natural killer" immune cells in the human body to distinguish between diseased cells, which they are meant to destroy, and normal cells, which they are meant to leave alone, has been revealed in new detail.

A natural killer cell attacks a diseased cell.
Credit: Image courtesy of Imperial College London

The mechanism used by 'Natural Killer' immune cells in the human body to distinguish between diseased cells, which they are meant to destroy, and normal cells, which they are meant to leave alone, is revealed in new detail in research published July 28 in PLoS Biology.

Understanding how this aspect of the body's natural defences works could help medical researchers develop new ways of boosting these defences to treat disease.

Natural Killer (NK) cells - a type of white blood cell - are a major component of the human body's innate immune system. Over 1,000 NK cells are found in every drop of blood. They provide a fast frontline defence against tumours, viruses and bacterial infections, by latching onto and killing cells in the human body that are cancerous or are infected with a virus or a bacterial pathogen.

On their journey round the human body NK cells regularly latch onto normal non-diseased cells too, before moving off, leaving them unharmed. Previously, the process by which NK cells made the right decision to kill or not kill another cell was unclear.

Now, a team of researchers from Imperial College London have used high speed microscopy imaging techniques to observe the NK cell decision making process in action. This has revealed striking differences in the behaviour of NK cells when interacting with healthy or diseased cells.

The outcome of the decision making process is determined by how receptors on the surface of the NK cell interact with proteins on the surface of the captured cell. Every NK cell has two types of surface receptors - activators, which turn the killing mechanism 'on' and inhibitors which turn the killing mechanism 'off'.

Professor Davis and his colleagues discovered that if a captured cell is diseased or cancerous, it interacts with a large number of the NK cell's activating receptors, which makes the NK cell stop dead in its tracks and spread out over the captured cell. During this spreading process the NK cell continuously reads the 'on' and 'off' signals from its surface contact with the captured cell. If the 'on' signals dominate, the NK cell prolongs contact with the captured cell and eventually kills it.

Conversely if the captured cell is healthy, it interacts with more of the NK cell's inhibiting receptors - and fewer of its activating receptors - meaning that the 'off' signals dominate and the 'stopping and spreading' process does not occur, allowing the NK cell to quickly move off in search of a new target.

Principal investigator of the new study, Professor Dan Davis from Imperial College London's Department of Life Sciences, explains:

"Scientists have known for a long time that the proteins on the surface on Natural Killer cells are involved in answering the 'to kill or not to kill?' question, but we've not known exactly how these molecular cues are translated into the correct response. Our research has shown that information gleaned from its surface receptors tells the Natural Killer cell whether to stop patrolling and commence killing, or to move off quickly, and harmlessly, in search of another target."

Dr Fiona Culley, lead author of the study from the National Heart and Lung Institute at Imperial, says that finding out how NK cells use this process to sift out diseased cells from normal ones paints a very clear picture of how these cells do their vital work:

"Considering that NK cells play such an important part in our immune response to cancer and disease, relatively little is known about their functionality - how exactly they work and how they interact with the cells they encounter inside us. This study adds significantly to our understanding of how Natural Killer cells distinguish between healthy and diseased cells."

The research was funded primarily by the Lister Institute for Preventative Medicine and the Medical Research Council, with additional support from the Biotechnology and Biological Sciences Research Council, the Royal Society and the Wellcome Trust.


Story Source:

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


Cite This Page:

Imperial College London. "Natural Born Killers: How The Body's Frontline Immune Cells Decide Which Cells To Destroy." ScienceDaily. ScienceDaily, 31 July 2009. <www.sciencedaily.com/releases/2009/07/090727203741.htm>.
Imperial College London. (2009, July 31). Natural Born Killers: How The Body's Frontline Immune Cells Decide Which Cells To Destroy. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2009/07/090727203741.htm
Imperial College London. "Natural Born Killers: How The Body's Frontline Immune Cells Decide Which Cells To Destroy." ScienceDaily. www.sciencedaily.com/releases/2009/07/090727203741.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Nigeria Ups Ebola Stakes on 1st Death

Nigeria Ups Ebola Stakes on 1st Death

Reuters - Business Video Online (July 29, 2014) Nigerian authorities have shut and quarantined a Lagos hospital where a Liberian man died of the Ebola virus, the first recorded case of the highly-infectious disease in Africa's most populous economy. David Pollard reports Video provided by Reuters
Powered by NewsLook.com
Running 5 Minutes A Day Might Add Years To Your Life

Running 5 Minutes A Day Might Add Years To Your Life

Newsy (July 29, 2014) According to a new study, just five minutes of running or jogging a day could add years to your life. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Poses Little Threat To U.S.: CDC

Ebola Outbreak Poses Little Threat To U.S.: CDC

Newsy (July 29, 2014) The Ebola outbreak in West Africa poses little threat to Americans, according to officials with the Centers for Disease Control and Prevention. Video provided by Newsy
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