Featured Research

from universities, journals, and other organizations

Tumor suppressor protein is a key regulator of immune response and balance

Date:
July 18, 2011
Source:
St. Jude Children's Research Hospital
Summary:
Scientists have identified a key immune system regulator, a protein that serves as a gatekeeper in the white blood cells that produce the "troops" to battle specific infections.

St. Jude Children's Research Hospital scientists have identified a key immune system regulator, a protein that serves as a gatekeeper in the white blood cells that produce the "troops" to battle specific infections.

Researchers demonstrated the protein, Tsc1, is pivotal for maintaining a balanced immune system and combating infections. Loss of the Tsc1 protein was associated with a reduction in the number of certain immune cells and a weaker immune response. The work appears in the July 17 online edition of the scientific journal Nature Immunology.

Scientists found that Tsc1 works by inhibiting the pathway that launches production of the specialized white blood cells known as effector T cells. Those cells are the backbone of the adaptive immune response, designed to respond, identify and destroy specific bacteria, viruses and other threats.

Working in mice with specially engineered immune systems, scientists showed Tsc1 also keeps cellular activity at a minimum in the white blood cells known as nave T cells. That process is known as quiescence.

Quiescence has long been recognized as crucial to proper immune function. But until now scientists were unclear how quiescence was established and maintained in nave T cells. "This study is the first to show that Tsc1 is a primary regulator of T cell quiescence," said Hongbo Chi, Ph.D., assistant member St. Jude Department of Immunology, and the study's senior author. The first author is Kai Yang, Ph.D., a postdoctoral fellow in Chi's laboratory.

"These findings not only advance understanding of the cell biology of the immune system but also have great potential for clinical applications in the future," Chi said. He speculated that the same process might also be important in regulating immune cells known as memory T cells that help the immune system recognize infectious agents encountered before and mount a rapid immune response.

Tsc1 is best known as a tumor suppressor, helping to prevent cancer development by inhibiting activity of the mTOR protein and the pathway that bears its name. The mTOR pathway plays a key role in cancer, metabolic disease and aging.

Now Chi and his colleagues demonstrated that in the immune system Tsc1 has a unique job. Through inhibition of the mTOR pathway, Tsc1 forces nave T cells to maintain minimal metabolic and cellular activity. Normally that would only change when nave T cells are activated and begin producing the more specialized effector T cells to combat a specific new threat.

In this study, scientists showed that loss of the Tsc1 protein predisposed affected T cells to premature activation, resulting in programmed cell death via the cell's suicide pathway. Consequently, the process depleted the supply of T cells as well as another group of specialized immune cells known as invariant natural killer T cells. The loss also dampened the ability of mice to combat bacterial infections. "We think maintaining T cell quiescence is central to preventing premature cell death and ensuring a productive immune response," Chi said.

Although more work is needed to understand mTOR regulation of T cell quiescence, this study offers a glimpse into the process. Tsc1 is part of a larger complex known to regulate mTOR activity. The mTOR protein is also a component in two larger complexes, known as mTORC1 and mTORC2. Chi and his colleagues demonstrated that nave T cell quiescence requires Tsc1 to keep mTORC1 activity at a low level. If Tsc1 is lost or shut down prematurely, mTORC1 activity increases, leading to premature activation of the immune cells, which results in various abnormalities and cell death.

Other authors are Geoffrey Neale, Douglas Green, both of St. Jude; and Weifeng He, formerly of St. Jude.

The research was supported in part by the National Institutes of Health, the Arthritis Foundation, the Lupus Research Institute and ALSAC.


Story Source:

The above story is based on materials provided by St. Jude Children's Research Hospital. Note: Materials may be edited for content and length.


Journal Reference:

  1. Kai Yang, Geoffrey Neale, Douglas R Green, Weifeng He, Hongbo Chi. The tumor suppressor Tsc1 enforces quiescence of naive T cells to promote immune homeostasis and function. Nature Immunology, 2011; DOI: 10.1038/ni.2068

Cite This Page:

St. Jude Children's Research Hospital. "Tumor suppressor protein is a key regulator of immune response and balance." ScienceDaily. ScienceDaily, 18 July 2011. <www.sciencedaily.com/releases/2011/07/110718111428.htm>.
St. Jude Children's Research Hospital. (2011, July 18). Tumor suppressor protein is a key regulator of immune response and balance. ScienceDaily. Retrieved September 24, 2014 from www.sciencedaily.com/releases/2011/07/110718111428.htm
St. Jude Children's Research Hospital. "Tumor suppressor protein is a key regulator of immune response and balance." ScienceDaily. www.sciencedaily.com/releases/2011/07/110718111428.htm (accessed September 24, 2014).

Share This



More Health & Medicine News

Wednesday, September 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Costs Keep Mounting

Ebola Costs Keep Mounting

Reuters - Business Video Online (Sep. 23, 2014) The WHO has warned up to 20,000 people could be infected with Ebola over the next few weeks. As Sonia Legg reports, the implications for the West African countries suffering from the disease are huge. Video provided by Reuters
Powered by NewsLook.com
Ebola Cases Could Reach 1.4 Million Within 4 Months

Ebola Cases Could Reach 1.4 Million Within 4 Months

Newsy (Sep. 23, 2014) Health officials warn that without further intervention, the number of Ebola cases in Liberia and Sierra Leone could reach 1.4 million by January. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Cases to Triple in Weeks Without Drastic Action

WHO: Ebola Cases to Triple in Weeks Without Drastic Action

AFP (Sep. 23, 2014) The number of Ebola infections will triple to 20,000 by November, soaring by thousands every week if efforts to stop the outbreak are not stepped up radically, the WHO warned in a study on Tuesday. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
5 Ways Men Can Prevent Most Heart Attacks

5 Ways Men Can Prevent Most Heart Attacks

Newsy (Sep. 23, 2014) No surprise here: A recent study says men can reduce their risk of heart attack by maintaining a healthy lifestyle, which includes daily exercise. 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:

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