Featured Research

from universities, journals, and other organizations

Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis

Date:
March 22, 2012
Source:
Brigham and Women's Hospital
Summary:
Medical professionals have suggested that the hygiene hypothesis explains the global increase of allergic and autoimmune diseases in urban settings. However, neither biologic support nor a mechanistic basis for the hypothesis has been directly demonstrated. Until now.

This concept of exposing people to germs at an early age (i.e., childhood) to build immunity is known as the hygiene hypothesis.
Credit: © Joanna Zielinska / Fotolia

Previous human studies have suggested that early life exposure to microbes (i.e., germs) is an important determinant of adulthood sensitivity to allergic and autoimmune diseases such as hay fever, asthma and inflammatory bowel disease.

Related Articles


This concept of exposing people to germs at an early age (i.e., childhood) to build immunity is known as the hygiene hypothesis.

Medical professionals have suggested that the hygiene hypothesis explains the global increase of allergic and autoimmune diseases in urban settings. It has also been suggested that the hypothesis explains the changes that have occurred in society and environmental exposures, such as giving antibiotics early in life.

However, neither biologic support nor a mechanistic basis for the hypothesis has been directly demonstrated. Until now.

Researchers at Brigham and Women's Hospital (BWH) have conducted a study that provides evidence supporting the hygiene hypothesis, as well as a potential mechanism by which it might occur.

The study was published online in the journal Science on the Science Express Web site on March 22, 2012.

The researchers studied the immune system of mice lacking bacteria or any other microbes ("germ-free mice") and compared them to mice living in a normal environment with microbes.

They found that germ-free mice had exaggerated inflammation of the lungs and colon resembling asthma and colitis, respectively. This was caused by the hyperactivity of a unique class of T cells (immune cells) that had been previously linked to these disorders in both mice and humans.

Most importantly, the researchers discovered that exposing the germ-free mice to microbes during their first weeks of life, but not when exposed later in adult life, led to a normalized immune system and prevention of diseases.

Moreover, the protection provided by early-life exposure to microbes was long-lasting, as predicted by the hygiene hypothesis.

"These studies show the critical importance of proper immune conditioning by microbes during the earliest periods of life," said Richard Blumberg, MD, chief for the BWH Division of Gastroenterology, Hepatology and Endoscopy, and co-senior study author, in collaboration with Dennis Kasper, MD, director of BWH's Channing Laboratory and co-senior study author. "Also now knowing a potential mechanism will allow scientists to potentially identify the microbial factors important in determining protection from allergic and autoimmune diseases later in life."

In light of the findings, the researchers caution that further research is still needed in humans.

This research was supported by the National Institutes of Health, Crohns Colitis Foundation of America, Harvard Digestive Diseases Center, Medizinausschuss Schleswig-Holstein, and Deutsche Forschungsgemeinschaft.


Story Source:

The above story is based on materials provided by Brigham and Women's Hospital. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. Olszak, D. An, S. Zeissig, M. P. Vera, J. Richter, A. Franke, J. N. Glickman, R. Siebert, R. M. Baron, D. L. Kasper, R. S. Blumberg. Microbial Exposure During Early Life Has Persistent Effects on Natural Killer T Cell Function. Science, 2012; DOI: 10.1126/science.1219328

Cite This Page:

Brigham and Women's Hospital. "Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis." ScienceDaily. ScienceDaily, 22 March 2012. <www.sciencedaily.com/releases/2012/03/120322142157.htm>.
Brigham and Women's Hospital. (2012, March 22). Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2012/03/120322142157.htm
Brigham and Women's Hospital. "Getting the dirt on immunity: Scientists show evidence for hygiene hypothesis." ScienceDaily. www.sciencedaily.com/releases/2012/03/120322142157.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

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
Doctor in NYC Quarantined With Ebola

Doctor in NYC Quarantined With Ebola

AP (Oct. 24, 2014) — An emergency room doctor who recently returned to the city after treating Ebola patients in West Africa has tested positive for the virus. He's quarantined in a hospital. (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