The essential prerequisite to the proper functioning of innate immunity is the “turning on” of the protein PI3-kinase. Once PI3-kinase is activated, the immune response is triggered, leading to the production of type I interferons, the spearhead of innate immunity, which destroy the body’s invaders. This discovery opens up new therapeutic prospects since it may suggest ways of restoring the function of innate immunity, which is overactivated in autoimmune diseases and inhibited in certain cancers. This work is published in the 18 February 2008 issue of the Journal of Experimental Medicine.
The body is often faced with attacks from outside (viral or bacterial infection) and sometimes from inside, because of the dysfunction of its own cells (cancer), and defends itself by activating its immune system. There are two types of defence. The first is innate immunity: this has no memory, and is permanently on guard to detect and destroy abnormal cells, tumor cells, or virus-infected cells. The second, which takes longer to initiate, is adaptive immunity, which specifically targets an invader. This response requires a education phase during which the cells of the immune system learn to recognize their enemy.
Dendritic cells, the body’s “sentinels”, are the first line of defence against invading pathogens: they recognize viruses and bacteria and then trigger an immune response, which, depending on the case, may be innate or adaptive. In response to an intruder, the so-called plasmacytoid dendritic cells can either produce large amounts of interferons, molecules that trigger a rapid response against viral infections, or “specialize” and become cells able to teach the immune system to recognize the pathogens.
At the Institut Curie, Vassili Soumelis(2) and his team (“Immunity and Cancer”, Inserm/Institut Curie Unit 653) have discovered how the dendritic cells choose between the two types of immune response. First, whatever the response, the presence of an intruder stimulates the TLR receptor inside the dendritic cells. Only then is the choice made between the two types of response. The PI3-kinase signaling pathway is activated, and the innate response is triggered. Kinase PI3 is the switch that turns on a whole cascade of proteins inside the cell. Information on the presence of an intruder in the body is thus transmitted to its final destination, in the cell’s nucleus, where the protein IRF-7 (transcription factor) modifies the expression of specific genes and so alters the cell’s behavior. In this specific case, IRF-7 induces the production of type 1 interferons (interferon-alpha, for example), which will bring about the destruction of the viruses and strongly activate various cells of the immune system.
Vassili Soumelis MD, PhD at the Institut Curie explains: “Activation of the protein PI3-kinase is one of the very first steps needed for the production of large quantities of type 1 interferons, leading to the triggering or strengthening of the innate immune response.”
In certain autoimmune diseases, like systemic lupus erythematosus(3) or Sjögren’s syndrome(4), this innate response overstimulated, leading to an abnormal defense reaction of the immune system, which attacks its own cells, tissues, or organs. In some cancers, on the other hand, the innate response is virtually absent.
It may be that the cancer cells are able to block the PI3-kinase signaling pathway. Through this discovery, Vassili Soumelis and his collaborators hope, in time, to develop new treatments for use in autoimmune diseases and oncology. By acting on PI3-kinase, it may be possible to adapt the innate response, so as to inhibit it in the treatment of autoimmune diseases and boost it in cancer treatment.
Céline Giustranti | alfa
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
Biological signalling processes in intelligent materials
18.07.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Life Sciences
18.07.2018 | Information Technology