Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research Reveals Inner Workings of Immune System ¡§Thermostat¡¨

22.08.2006
The immune system runs hot, sending out inflammatory infection-fighting proteins, then cools down by releasing anti-inflammatory soothers. A Brown University-led research team explains how this ¡§thermostat¡¨ works in the Journal of Immunology.

When bacteria, viruses or parasites attack, immune system cells unleash the soldiers. These ¡§hot¡¨ protein compounds kill invaders ¡V but also trigger inflammation, which, if unchecked, can destroy tissue, induce shock and kill the host. So immune system cells let loose another protein compound to cool down the immune response.

Precisely how this immune system ¡§thermostat¡¨ operates is unclear. The leading hypothesis is that these compounds ¡V which act as furnace and air conditioner ¡V battle it out over control of the system¡¦s inflammatory response.

But new research, led by George Yap of Brown University, shows that these cytokines don¡¦t operate independently and in opposition. They operate in harmony and are controlled by the same master. In work published in the Journal of Immunology, Yap and his team show that the ¡§cool¡¨ anti-inflammatory protein compound known as Interleukin 10 is activated by Interferon-£^, a class of proteins secreted by a class of white blood cells known as T helper 1 cells. The team then traced secretion of Interferon-£^ indirectly to tyrosine kinase 2, or tyk2, the same protein that signals ¡§hot¡¨ inflammatory cytokines Interleukin 12 and Interferon-£ and Interferon-£].

¡§Under the prevailing paradigm, scientists believe that the pro- and anti-inflammatory arms of the immune system just antagonize each other,¡¨ Yap said. ¡§Here we show that they actually induce each other. ¡¥Hot¡¦ cytokines don¡¦t inhibit ¡¥cool¡¦ ones ¡V they trigger their production. Wounding, in effect, triggers a healing process.¡¨

In previous research, Yap discovered that mutant mice with a naturally defective tyk2 gene were immune to arthritis, a condition caused by inflammation. But these mutants were much more susceptible to opportunistic infections. Why? Without tyk2, Yap found, mice didn¡¦t make enough of the pro-inflammatory warriors that destroy harmful bugs and cause inflammation. This finding established the notion that tyk2 signaling controlled Interleukin 12, the furnace side of the system. But what controlled Interleukin 10, the air conditioner?

To find out, Yap and his team conducted a series of experiments in mutant mice infected with the parasite Toxoplasma gondii. They found that Interleukin 10 production by T helper 1 cells is triggered by Interferon-£^ƒnƒ{ƒnbut not directly. Another cell, an antigen presenting cell or APC, sends a stimulatory signal back to the T helper 1 cell, ordering it to make Interleukin 10.

¡§What we see is that the ¡¥hot¡¦ and ¡¥cool¡¦ arms of the immune system aren¡¦t independently regulated,¡¨ Yap said. ¡§They talk to each other and respond in a dynamic and coordinated fashion.¡¨

Yap said the findings should send a message to drug companies designing and testing tyk2-inhibiting medicines for arthritis and other autoimmune diseases. Block tyk2 function, Yap said, and patients will be more prone to infection ¡V and their arthritis may not be relieved. ¡§There could be a downside to these drugs,¡¨ he said.

Brown graduate student Michael Shaw and Brown Medical School student Mark Scott contributed to the research. Gordon Freeman of the Dana-Farber Cancer Institute, Barbara Fox and David Bzik of Dartmouth Medical School and Yasmine Belkaid of the National Institute of Allergy and Infectious Disease served as collaborators.

The National Institute of Allergy and Infectious Diseases funded the research.

Wendy Lawton | EurekAlert!
Further information:
http://www.brown.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>