Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Microbes start immune response by sneaking inside cells

17.04.2007
New insights could lead to better vaccines, treatments for rheumatoid arthritis, study suggests

Immune cells that are the body’s front-line defense don’t necessarily rest quietly until invading bacteria lock onto receptors on their outside skins and rouse them to action, as previously thought. In a new paper, University of Michigan scientists describe their findings that bacteria can barge inside these guard cells and independently initiate a powerful immune response.

The study, published online ahead of print in the April issue of the journal Immunity and accompanied by a special commentary, adds important new details to an emerging picture of how the body recognizes invading bacteria and responds. The work of the U-M team and researchers elsewhere — now taking place in laboratory animal studies — offers a different way of thinking about how best to design future human vaccines, as well as drugs that could more precisely target the body’s inflammatory response in rheumatoid arthritis and some other autoimmune diseases.

“In our study, the presence of bacterial microbes inside the cell is what triggers the immune response. That creates a new perspective for developing new drugs,” says senior author Gabriel Nunez, M.D., the Paul H. de Kruif professor of pathology at the U-M Medical School and a member of the U-M Comprehensive Cancer Center.

For years, scientists have believed that when bacteria invade the body, they set off alarms in the immune system by interacting with receptors on a cell’s surface. But, now new studies are revealing that bacteria can also plunge inside immune system cells and trigger the immune response there. In the new study, Nunez’ team sheds light on one major pathway in which this process occurs.

When invading bacteria enter immune system cells, a protein called cryopyrin, present in the fluid inside the cells, responds and activates a key pathogen-fighting molecule, Nunez’ team reported last year in Nature. Cryopyrin is implicated in the development of several inflammatory syndromes characterized by recurrent fever, skin rash and arthritis.

Cryopyrin triggers a key enzyme involved in the body’s inflammatory response, capsase-1, which in turn causes production of IL-1beta, a powerful molecule which signals the immune system to attack pathogens and induces fever to help the body fend off infection. IL-1beta plays an important role, too, in excessive immune system activity in inflammatory diseases.

The researchers report in the new paper how cryopyrin is activated to start the process. In experiments that exposed mouse immune cells called macrophages to bacteria, Thirumala-Devi Kanneganti, Ph.D., a U-M research investigator in pathology, and Mohamed Lamkanfi, Ph. D, a U-M research fellow, the study’s co-first authors, find that cryopyrin’s call to action inside the cells occurs without requiring a well-known set of cell-surface receptors called Toll-like receptors or TLRs. ”We prove that these TLRs are not required to activate cryopyrin. That is a major step,” says Nunez.

Instead, bacteria were able to enter the cells through a pore in the cell membrane, and stimulate the cryopyrin-initiated immune response without activating TLRs. The researchers discovered that a protein called pannexin-1 creates the pore, like a devious undersea diver drilling a hole in a ship hull.

The team’s work joins a growing body of research revealing the importance of recently discovered receptors such as cryopyrin inside cells, known collectively as NOD-like receptors. Knowledge about NOD-like receptors is moving forward rapidly and will contribute to a fuller understanding of the human immune system, say the U-M researchers.

Anne Rueter | EurekAlert!
Further information:
http://www.umich.edu

Further reports about: Receptors U-M cryopyrin immune response immune system

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
18.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>