Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


How does the immune system isolate and destroy intruders?

Dendritic cells are the body’s “watchdogs”. They recognize and then degrade pathogens, isolating characteristic fragments that are recognized by the immune system thus triggering targeted responses. At the Institut Curie, CNRS and Inserm researchers have now discovered how dendritic cells produce these fragments.

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
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

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 3-D wiring technique brings scalable quantum computers closer to reality

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...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

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...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

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...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>