Working model for the role of exosomes in immune responses.
After the uptake of incoming pathogens in the periphery, immature or maturing dendritic cells (green) generate peptide-MHC complexes. Some of these complexes could be secreted on exosomes, and locally sensitize other dendritic cells (blue) that have not encountered the pathogen directly. As a result of the effects of inflammation, all of these dendritic cells migrate out of the tissue towards the draining lymph nodes. Although maturing dendritic cells seem to secrete fewer exosomes than immature cells, an exchange of exosomes inside the lymph nodes between newly arrived (and not fully mature) and resident dendritic cells could take place also. Therefore, exosome production would increase the number of dendritic cells that bear the revelant peptide-MHC complexes, and thereby amplify the magnitude of immune responses. In the absence of inflammation, spontaneous migration of exosome-bearing dendritic cells could contribute to tolerance induction.
In this picture a mature dendritic cell (the cell on the right with dendrites) is moving towards a T lymphocyte (little rounded cell). The contact between a mature dendritic cell and a T lymphocytes is the initial step of an immune response.
Exosomes are minute, natural membrane vesicles secreted by various types of cells of the immune system. They are of enormous interest to oncologists, who are now using them in clinical trials as tumor-antigen bearers to trigger tumor rejection by the body.
On the basis of studies in vitro and in mice, INSERM doctors and research scientists at the Institut Curie proposed a novel mode of functioning of exosomes in the December 2002 issue of Nature Immunology. It seems that exosomes can indirectly stimulate the immune system. When they are secreted by dendritic cells (the immune system’s "sentries"), they are captured by other dendritic cells, which subsequently bring about the triggering of the immune response. It is as if one of the functions of the exosomes is to transfer their specific membrane-borne antigens to other dendritic cells, thus multiplying the number of "sentries" alerted and raising the defense potential of the immune system. If this mechanism is confirmed, it would partly explain how exosomes participate in tumor rejection in vivo.
These studies will undoubtedly lead to improvements in the use of antigen-bearing exosomes in cancer immunotherapy.
Catherine Goupillon | Institut Curie
The dense vessel network regulates formation of thrombocytes in the bone marrow
25.07.2017 | Rudolf-Virchow-Zentrum für Experimentelle Biomedizin der Universität Würzburg
Fungi that evolved to eat wood offer new biomass conversion tool
25.07.2017 | University of Massachusetts at Amherst
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
25.07.2017 | Physics and Astronomy
25.07.2017 | Earth Sciences
25.07.2017 | Life Sciences