They have revealed the hitherto unknown role of the NADPH oxidase NOX2 in immune recognition, thus shedding light on how the immune system works and so enhancing our capacity to manipulate and use it therapeutically. This discovery, published in the July 14, 2006 issue of Cell, should help us to fine-tune the immune response in the treatment of certain diseases like cancer.
The body is constantly under attack from outside forces (viruses and bacteria) and sometimes from forces within (cellular abnormalities leading to cancer). Its defensive response is to activate the immune system. There are two types of defense. First, there is innate immunity, which has no memory and so is constantly on the lookout for infectious agents to destroy. Second, there is adaptive immunity, which over time acquires memories of particular pathogens.
This requires a “learning” phase in which the dendritic cells degrade pathogenic agents into characteristic fragments, the epitopes, and then present these epitopes to the T and B lymphocytes, thereby initiating immune responses. The pathogen’s profile is memorized through this learning process and the next time the same pathogen is encountered the body immediately recognizes it and so is able to respond rapidly.
NOX2, immunity’s double agent
In innate immune responses, the invader is totally destroyed, a process in which the NADPH oxidase NOX2 plays a central role. In neutrophils, the cells at the heart of innate immune responses, NOX2 ensures the complete destruction of invading pathogens so they are no longer harmful to the body.
In adaptive immune responses, the dendritic cells’ challenge is to degrade the pathogen just partially, thus preserving sufficiently representative fragments that can be presented to the T and B lymphocytes. Ariel Savina at the Institut Curie, in the Inserm team of Sebastian Amigorena(1), has been studying how dendritic cells, the body’s “watchdogs”, achieve this controlled degradation of pathogens into epitopes. What they have found is that NOX2 is also implicated in adaptive immune responses. Its role in this case contrasts with that in neutrophils. NOX2 regulates the pH in the compartments (phagosomes) of the dendritic cells where pathogens are degraded, thus ensuring suitable acidity.
This pH regulation slows the degradation of the pathogens thus avoiding their complete destruction, which allows the dendritic cells to trigger a specific and efficient adaptive immune response.
These new findings shed light on how the immune system works and should help us to optimize one of the most promising approaches to cancer treatment: immunotherapy, in which the immune system is used to destroy tumor cells. The Institut Curie has for many years been participating actively in the development of innovative immunotherapeutic strategies. Two clinical trials are currently under way at the Institut Curie, one in patients with choroidal melanoma and another in cervical cancer patients. The results are expected some time in 2007.
(1) Sebastian Amigorena is CNRS Director of Research and Head of Inserm/Institut Curie Unit 653 “Immunity and cancer”.
Catherine Goupillon | alfa
127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere
How gut bacteria can make us ill
18.01.2017 | Helmholtz-Zentrum für Infektionsforschung
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Materials Sciences
18.01.2017 | Information Technology
18.01.2017 | Ecology, The Environment and Conservation