Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

HIV exploits competition among T cells

18.10.2006
Research points to new strategy for AIDS vaccination

A new HIV study shows how competition among the human immune system's T cells allows the virus to escape destruction and eventually develop into full-blown AIDS. The study, which employs a computer model of simultaneous virus and immune system evolution, also suggests a new strategy for vaccinating against the virus – a strategy that the computer simulations suggest may prevent the final onset of AIDS.

The research, which is slated for publication in Physical Review Letters, is available online at http://arxiv.org/abs/q-bio.PE/0610018.

"Competition among T cells exerts a small influence for most diseases, but it's fatal for HIV," said study co-author Michael Deem, Rice University's John W. Cox Professor in Biochemical and Genetic Engineering and professor of physics and astronomy.

The new computer model, created by Deem and Guanyu Wang, now an assistant professor of physics at George Washington University, is the first to accurately reproduce all three stages of HIV infection. The first is marked by an initial spike in virus production that's immediately followed by dramatic drop as the immune system recognizes the threat, mounts a defense and destroys most of the invading viruses. The second phase is a long period of clinical latency that can last up to 10 years. In this phase, a small amount of virus mutates fast enough to escape initial detection and continues to mutate over time. The third phase, AIDS, occurs when the virus has changed so much that the body's T cells are no longer effective at keeping it in check.

Deem and Wang's computer model accurately describes all three phases of HIV infection by incorporating a key component: competition among T cells. The model includes two forms of competition. The first form leads to a phenomenon known as deceptive imprinting, or original antigenic sin. Original antigenic sin is the tendency for memory immune cells produced in response to a first viral infection to suppress the creation of new immune cells in response to a second infection by a related strain. The second type of competition, immunodominance, occurs when several viral strains simultaneously infect one person. In this case, T cells compete to recognize the different strains. The winners – the T cells that the body produces in mass quantities to fight the disease – are the ones with the best overall record against the most recogniztable strains. Among the losers, however, there may be T cells that better control the other less recognizable, but still deadly, strains.

"Once the immune system chooses a winning set of T cells, it has a natural tendency to go with those cells when it's confronted by new strains of the same disease in the future," Deem said. "For HIV, which mutates rapidly, this is an Achilles' heel. We found a direct correlation between the level of competition among T cells and the rate at which the virus escaped."

Deem said one strategy to combat this effect would be to vaccinate against the strains of HIV that will inevitably evolve in the body in a manner that was designed to reduce immunodominance. One such strategy – polytopic vaccination – involves giving vaccines against different strains of the same disease simultaneously in different parts of the body. The approach capitalizes on the fact that different lymph nodes – the sites where T cells compete to be chosen as the winners against a particular disease – act as collection points for different parts of the body. Moreover, because it takes 4-5 days for T cells produced in a lymph node to begin to leave it, the possibility exists to set up simultaneous, independent competition against each of the multiple strains that will evolve by injecting each strain simultaneously so that they drain to different lymph nodes. In this case, no single T cell is chosen as a winner. Instead, a separate winner for each strain is picked in each affected lymph node before immunodominance can come into play.

"In our simulations, this strategy appears effective at all but eliminating competition among T cells," Deem said. "As a result, HIV remained in a state of permanent latency and was never able to escape the immune system's grasp to develop into AIDS."

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

More articles from Studies and Analyses:

nachricht New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>