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 The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

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...

Im Focus: Studying fundamental particles in materials

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...

Im Focus: Designing Architecture with Solar Building Envelopes

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>