Navigation Links
HIV exploits competition among T-cells

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 befo re 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."


'"/>

Source:Rice University


Related biology news :

1. Neandertal femur suggests competition with hyenas and a shift in landscape use
2. Birth rate, competition are major players in hominid extinctions
3. Variation in womens X chromosomes may explain differences among individuals, between sexes
4. Disease diagnosis, biodefense among UH chemical research projects
5. HIV drug resistance increasing in UK and among highest in the world
6. Why we give: New study finds evidence of generosity among our early human ancestors
7. Alcoholism, smoking and genetics among Plains American Indians
8. Genetic and environmental influences on alcohol consumption among rhesus monkeys
9. Skin disease common among Hispanic farmworkers in North Carolina, research shows
10. Cell barrier shows why bird flu not so easily spread among humans
11. Higher risk for cervical cancer seen among women infected with multiple HPV types
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:11/14/2016)... , Nov. 14, 2016  Based on ... market, Frost & Sullivan recognizes FST Biometrics ... Award for Visionary Innovation Leadership. FST Biometrics ... biometric identification market by pioneering In Motion ... for instant, seamless, and non-invasive verification. This ...
(Date:6/22/2016)...  The American College of Medical Genetics and Genomics was ... as one of the fastest-growing trade shows during the Fastest ... in Las Vegas . ... in each of the following categories: net square feet of ... attendees. The 2015 ACMG Annual Meeting was ranked 23 out ...
(Date:6/22/2016)... 22, 2016 On Monday, the Department of ... to share solutions for the Biometric Exit Program. The ... Border Protection (CBP), explains that CBP intends to add ... the United States , in order to ... imposters. Logo - http://photos.prnewswire.com/prnh/20160622/382209LOGO ...
Breaking Biology News(10 mins):
(Date:12/2/2016)... The immunohistochemistry (IHC) market is projected to reach ... during the forecast period of 2016 to 2021 dominated by immunohistochemistry ... the largest share of immunohistochemistry (IHC) market, by end user.   ... , , ... across 225 pages, profiling 10 companies and supported with 181 tables ...
(Date:11/30/2016)... ... November 30, 2016 , ... BEI Kimco, ... Actuator with a flexure design that ensures high alignment accuracy by preventing unwanted ... is ideally suited where extreme precision is required, such as in medical equipment, ...
(Date:11/30/2016)... New York , November 30, 2016 ... consolidated as a few players hold a dominant share ... Group, Charles River Laboratories International, Inc., and Merck KGaA, ... market in 2015. Transparency Market Research observes that these ... are focused on development products that are do not ...
(Date:11/30/2016)... 2016 Biotest Pharmaceuticals Corporation (BPC), a leading ... the addition of its newest plasma collection center located ... . The 15,200 square foot state-of-the-art facility officially opened ... brings the total number of BPC,s plasma collection centers ... BPC,s Chief Executive Officer said "We are pleased to ...
Breaking Biology Technology: