Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rac 1 and 2, two proteins essential to triggering of the immune response

23.08.2004


When a dendritic cell meets a T cell… The dendritic cell and its “arms” can be seen on the left of the images. On the right is a smaller T cell. In the first image, the dendritic cell reaches out in search of a T cell. In the second image, it finds a T cell and extends its arms towards it. In the third image, the dendritic cell entraps the T cell. © F. Benvenuti/Institut Curie


In this dendritic cell, the proteins Rac 1 and 2 are inactive. The dendritic cell is "unaware" of the presence of the T cell. © F. Benvenuti/Institut Curie


The dendritic cells act as the body’s sentries, standing guard around the clock. As soon as they detect a potential enemy, they alert the T cells, whose role is to defend the body.

At the Institut Curie, CNRS researchers in an Inserm laboratory have filmed the encounter of dendritic cells and T cells. They have shown that this "rendez-vous", which is indispensable for the activation of the immune system, cannot take place in the absence of the proteins Rac 1 and 2. Published in the August 20, 2004 issue of Science, this discovery yields new information on the immune system and could in time pave the way for advances in immunotherapy.

Our immune system is on call round the clock. Whenever a foreign body intrudes (virus, bacterium…), or even in response to the anarchic proliferation of the body’s own cells (cancer), the immune system sounds the alarm.



Dendritic cells are the "sentries" responsible for detecting the presence of an intruder in our body. When they locate a potentially dangerous cell, they partially ingest it and isolate a characteristic fragment, an antigen(1). Bearing this fragment they then migrate to the lymph nodes, where the T cells are to be found. The dendritic cells present the antigen to T cells, thus enabling them to recognize the enemy, which they must eliminate. Once informed, T cells launch a targeted offensive to rid the body of bacteria, tumor cells or virus-infected cells. At the Institut Curie, Sebastian Amigorena(2) and his team are studying how the body’s sentries identify the antigen and then present it to the T cells.

The dendritic cell stretches out its arms…

To observe the in vivo meeting between dendritic cells and T cells in the lymph nodes, Sebastian Amigorena and colleagues, in partnership with Luc Fetler(3), have used the highly sophisticated technique of two-photon microscopy (see box). This is the first time in Europe that two-photon microscopy has been utilized to follow the triggering of immune responses in vivo, in intact organs.

Rather like starfish, dendritic cells have several "arms", formed by membrane extensions. Once they reach the lymph nodes, the dendritic cells stretch out these arms in their search for T cells(4).

…and entraps the T cell

When a T cell is found, the dendritic cell’s arms stretch towards it by extension of the cell membrane and "engulf" it. The Institut Curie scientists noted that this "engulfment", which is essential to effective triggering of an immune response, cannot occur without the presence of proteins Rac 1 and 2(5). These two proteins control the extension of the dendritic cell membrane when the T cell is contacted. When Rac 1 and 2 are inactivated, the meeting between the T cells and the dendritic cells does not happen and as a result the immune response is not triggered.

This discovery should lead to optimization of one of the promising approaches to cancer treatment – immunotherapy, in which the immune system is used to destroy tumor cells. By measuring the expression and activation state of Rac 1 and 2, it may be possible to assess, and if necessary enhance, the efficacy of dendritic cells in initiating the immune response.

Catherine Goupillon | alfa

More articles from Life Sciences:

nachricht The Secret of the Rock Drawings
24.05.2019 | Max-Planck-Institut für Chemie

nachricht Chemical juggling with three particles
24.05.2019 | Rheinische Friedrich-Wilhelms-Universität Bonn

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: New studies increase confidence in NASA's measure of Earth's temperature

A new assessment of NASA's record of global temperatures revealed that the agency's estimate of Earth's long-term temperature rise in recent decades is accurate to within less than a tenth of a degree Fahrenheit, providing confidence that past and future research is correctly capturing rising surface temperatures.

The most complete assessment ever of statistical uncertainty within the GISS Surface Temperature Analysis (GISTEMP) data product shows that the annual values...

Im Focus: The geometry of an electron determined for the first time

Physicists at the University of Basel are able to show for the first time how a single electron looks in an artificial atom. A newly developed method enables them to show the probability of an electron being present in a space. This allows improved control of electron spins, which could serve as the smallest information unit in a future quantum computer. The experiments were published in Physical Review Letters and the related theory in Physical Review B.

The spin of an electron is a promising candidate for use as the smallest information unit (qubit) of a quantum computer. Controlling and switching this spin or...

Im Focus: Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a...

Im Focus: Quantum Cloud Computing with Self-Check

With a quantum coprocessor in the cloud, physicists from Innsbruck, Austria, open the door to the simulation of previously unsolvable problems in chemistry, materials research or high-energy physics. The research groups led by Rainer Blatt and Peter Zoller report in the journal Nature how they simulated particle physics phenomena on 20 quantum bits and how the quantum simulator self-verified the result for the first time.

Many scientists are currently working on investigating how quantum advantage can be exploited on hardware already available today. Three years ago, physicists...

Im Focus: Accelerating quantum technologies with materials processing at the atomic scale

'Quantum technologies' utilise the unique phenomena of quantum superposition and entanglement to encode and process information, with potentially profound benefits to a wide range of information technologies from communications to sensing and computing.

However a major challenge in developing these technologies is that the quantum phenomena are very fragile, and only a handful of physical systems have been...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

On Mars, sands shift to a different drum

24.05.2019 | Physics and Astronomy

Piedmont Atlanta first in Georgia to offer new minimally invasive treatment for emphysema

24.05.2019 | Medical Engineering

Chemical juggling with three particles

24.05.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>