Navigation Links
Why Immune System Doesn't Attack Small Intestine?

Why the body's immune system - perpetually on guard against foreign microbes like bacteria – doesn't attack tissues in the small intestine that harbor millions// of bacteria cells - Answers to one of the oldest questions in human physiology – is found by researchers at Dana-Farber Cancer Institute in a study published in the February issue of Nature Immunology and which is currently available on the journal's Web site as an advanced online publication.

Investigators led by Shannon Turley, PhD, of Dana-Farber identify an unlikely group of peacemakers: lymph node cells that instruct key immune system cells to leave healthy tissue alone. The finding, which illuminates a previously unknown corner of the human immune system, may lead to new forms of treatment for autoimmune diseases such as Type 1 diabetes and multiple sclerosis.

"We've discovered that cells not generally thought of as part of the immune system actually play an important role in protecting the intestine from immune system attack," says Turley. "Because the cells are found in lymph nodes throughout the body, they may offer a way of suppressing a variety of autoimmune diseases," which result from immune system assault on healthy tissue.

The immune system distinguishes between normal and foreign agents by small proteins, called antigens, on the cell surface. In parts of the body, such as the pancreas, that is sheltered from the outside environment, cells known as dendritic cells display the antigens of their normal neighbors in a way that puts the immune system "at ease." By reading those antigens without being on alert, the immune system's T cells learn that such cells are off-limits to attack.

For years, scientists have wondered whether the same mechanism is at work in tissues that come in regular contact with bacteria and other microbial organisms. The small intestine, for example, which absorbs essential nutrients from food and drink and protects the body from invasive microbes, is literally teeming with bacteria, which help break down waste. The presence of so many bacteria is a potential trigger for an immune system response. Why do T cells almost always ignore the small intestine, leaving this vital tissue unharmed?

"It's obvious that T cells must be able to ignore – or become 'tolerized' to – normal intestinal tissue," states Turley, who is also an assistant professor of pathology at Harvard Medical School. "But it has been unclear how dendritic cells, which are extremely sensitive to microbial agents such as bacteria, teach T cells to resist attacking healthy intestinal cells."

In the new study, Turley and her colleagues found that, in fact, dendritic cells aren't essential in creating tolerance in T cells. Instead, and unexpectedly, tolerance is produced by stromal cells from nearby lymph nodes. Although they aren't classified as "professional antigen-presenters," as dendritic cells are, the stromal cells serve the same purpose: exhibiting normal-cell antigens to the immune system.

"Our study points to a previously unknown mechanism of immune system tolerance," Turley explains. "When you think of the conditions in the small intestine, with so many millions of bacteria cells and so much opportunity for dendritic cells to stimulate an immune attack, it's remarkable that intestinal tissue is so rarely the target of an immune attack. Our findings demonstrate that the immune system has features that remain to be discovered."

Source-Eurekalert
RI
'"/>




Related medicine news :

1. Immune cells halt round in space
2. Immune function could benefit from exercise
3. Reviving the Immune System
4. Wrestling found To Be Good for the Immune System
5. Immune Boost With LHRH To Help Cancer And Transplant Patients
6. Researchers Find Out The Cause Of Immune Attacks Behind Hearing Loss
7. Block Immune System Chemical For Treating Asthma
8. Immune Response Of Human Beings Can Be Re-energized
9. Weizmann Institute of Science says Immune Cells Could Help Maintain Brain Function
10. Antidepressant drugs interacts with Immune cells
11. Specific Immune Mechanism against DNA viruses
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand ... project," said Christina Austin - CEO of Pixel Film Studios. , ProHand Cartoon’s ... within Final Cut Pro X . Simply select a ProHand generator and drag ...
(Date:6/25/2016)... ... June 25, 2016 , ... Conventional wisdom preaches the benefits of moderation, ... the latter, setting the bar too high can result in disappointment, perhaps even self-loathing. ... toward their goal. , Research from PsychTests.com reveals that behind the ...
(Date:6/24/2016)... ... 2016 , ... The Pulmonary Hypertension Association (PHA) learned during ... two significant new grants to support its work to advance research and patient ... recognizing patients, medical professionals and scientists for their work in fighting pulmonary hypertension ...
(Date:6/24/2016)... TX (PRWEB) , ... June 24, 2016 , ... People ... part in Genome magazine’s Code Talker Award, an essay contest in which patients and ... an award to be presented at the 2016 National Society of Genetic Counselors (NSGC) ...
(Date:6/24/2016)... ... , ... National recruitment firm Slone Partners is pleased to announce ... experience, as Vice President of North American Capital Sales at HTG Molecular . ... sales team in the commercialization of the HTG EdgeSeq system and associated reagents in ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... June 24, 2016 Research ... "Structural Electronics 2015-2025: Applications, Technologies, Forecasts" ... In-Mold Electronics, Smart Skin, Structural Health ... Structural electronics involves electronic and/or electrical ... structures, replacing dumb structures such as vehicle bodies ...
(Date:6/24/2016)... Calif. , June 24, 2016  American Respiratory Labs (ARL), ... is now able to perform sophisticated lung assessments in patients, homes, ... , Inc. Patients are no longer limited to ... EasyOne PRO ® , ARL patients like Jeanne R. of ... in the comfort of her own home. ...
(Date:6/24/2016)... , June 24, 2016   Pulmatrix, Inc ... company developing innovative inhaled drugs, announced today that it ... Russell Investments reconstituted its comprehensive set of U.S. ... "This is an important milestone for Pulmatrix," said ... increase shareholder awareness of our progress in developing drugs ...
Breaking Medicine Technology: