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
First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife
Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering