Featured Research

from universities, journals, and other organizations

Skin's immune peacekeepers discovered

Date:
October 19, 2011
Source:
Centenary Institute
Summary:
There are more bacteria living on our skin and in our gut than cells in our body. We need them. But until now no one knew how the immune system could tell that these bacteria are harmless. Researchers in Sydney have discovered a set of peacekeepers -- immune cells in the outer layers of our skin that stop us from attacking friendly bacteria.

Image of langerhans cells in skin (from a genetically engineered mouse where LCs express yellow fluorescent protein).
Credit: Centenary Institute, Barbara Fazekas de St Groth

There are more bacteria living on our skin and in our gut than cells in our body. We need them. But until now no one knew how the immune system could tell that these bacteria are harmless. Centenary Institute researchers in Sydney have discovered a set of peacekeepers -- immune cells in the outer layers of our skin that stop us from attacking friendly bacteria.

Related Articles


The work will open the way to new therapeutic options for immune-mediated diseases such as inflammatory bowel disease, of which Australia has some of the world's highest rates.

In a paper published October 17 in the Proceedings of the National Academy of Sciences (PNAS), Professor Barbara Fazekas de St Groth and her team have shown that the immune cells in the outer layer of the skin constantly act as peacekeepers to stop the immune system from reacting the way it normally would. Known as Langerhans cells, they resisted every attempt by the researchers to get them to generate an immune response.

The researchers worked with a group of mice in which only the Langerhans cells could stimulate the immune system. They then activated the Langerhans cells and measured the response.

"No matter what we threw at them to get them to activate a long-term immune response, the Langerhans cells always induced immune tolerance," Prof Fazekas says.

This result seems to go against the prevailing wisdom in immunology about the workings of dendritic cells, the class of immune cell to which Langerhans cells belong.

Dendritic cells engulf bacteria, viruses or other invaders and put a marker from that invader, known as an antigen, on a protein that can bind to other immune cells.

The antigen reprograms passing T cells, the workhorses of the immune system, which then set off a cascade of responses that eventually lead to the destruction of anything displaying that antigen.

However, the Centenary team (which is affiliated with the University of Sydney and RPA Hospital) found Langerhans cells are very different from other dendritic cells: after turning on the helper T cells, they tell them to self-destruct instead.

"This is the opposite of what you'd usually expect. In previous studies of immune cells, if there was a flurry of activity, we assumed it was the start of a long-term immune response," Prof Fazekas says.

However, the immune system is a layered defence¬ -- the next layer of skin has different kinds of dendritic cells, which program on-going responses against bacteria. So if bacteria penetrate deep enough to meet these cells, the immune response will kill them.

In inflammatory bowel disease, which afflicts thousands of Australians, the immune system is activated against the gut bacteria, which are usually left alone.

This discovery opens up possible ways to figure out why this disorder occurs and to find treatments to a range of diseases of the immune system.

"There is so much we don't know about the immune system, but sometimes just mimicking what the system does, like we do with vaccines, can work very well" Prof Fazekas says,

"If we do manage to mimic what Langerhans cells do, then we could develop treatments that would precisely tolerise against specific antigens -- just like the immune system of the skin does now."

Centenary Institute executive director Professor Mathew Vadas says this latest paper comes just weeks after Centenary researcher Patrick Bertolino made the front cover of PNAS for his paper on immune response in the liver.

"The Centenary Institute is interested in understanding how the immune system works -- these discoveries and others already in the pipeline here are a major step forward towards that goal," Prof Vadas says.


Story Source:

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


Journal Reference:

  1. Elena Shklovskaya, Brendan J. O'Sullivan, Lai Guan Ng, Ben Roediger, Ranjeny Thomas, Wolfgang Weninger, and Barbara Fazekas de St Groth. Langerhans cells are precommitted to immune tolerance induction. PNAS, October 17, 2011 DOI: 10.1073/pnas.1110076108

Cite This Page:

Centenary Institute. "Skin's immune peacekeepers discovered." ScienceDaily. ScienceDaily, 19 October 2011. <www.sciencedaily.com/releases/2011/10/111017155616.htm>.
Centenary Institute. (2011, October 19). Skin's immune peacekeepers discovered. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2011/10/111017155616.htm
Centenary Institute. "Skin's immune peacekeepers discovered." ScienceDaily. www.sciencedaily.com/releases/2011/10/111017155616.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Best Tips to Curb Holiday Carbs

The Best Tips to Curb Holiday Carbs

Buzz60 (Dec. 19, 2014) — It's hard to resist those delicious but fattening carbs we all crave during the winter months, but there are some ways to stay satisfied without consuming the extra calories. Vanessa Freeman (@VanessaFreeTV) has the details. Video provided by Buzz60
Powered by NewsLook.com
Sierra Leone Bikers Spread the Message to Fight Ebola

Sierra Leone Bikers Spread the Message to Fight Ebola

AFP (Dec. 19, 2014) — More than 100 motorcyclists hit the road to spread awareness messages about Ebola. Nearly 7,000 people have now died from the virus, almost all of them in west Africa, according to the World Health Organization. Video provided by AFP
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) — In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
The Best Protein-Filled Foods to Energize You for the New Year

The Best Protein-Filled Foods to Energize You for the New Year

Buzz60 (Dec. 19, 2014) — The new year is coming and nothing will energize you more for 2015 than protein-filled foods. Fitness and nutrition expert John Basedow (@JohnBasedow) gives his favorite high protein foods that will help you build muscle, lose fat and have endless energy. Video provided by Buzz60
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