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:4/19/2016)... UAE, April 20, 2016 The ... as a compact web-based "all-in-one" system solution for all ... fingerprint reader or the door interface with integration authorization ... access control systems. The minimal dimensions of the access ... into the building installations offer considerable freedom of design ...
(Date:4/14/2016)... 2016 BioCatch ™, the ... announced the appointment of Eyal Goldwerger as ... Goldwerger,s leadership appointment comes at a time of ... deployment of its platform at several of the world,s ... discerns unique cognitive and physiological factors, is a winner ...
(Date:3/31/2016)... , March 31, 2016  Genomics firm Nabsys has ... CEO, Barrett Bready , M.D., who returned to ... the original technical leadership team, including Chief Technology Officer, ... Product Development, Steve Nurnberg and Vice President of Software ... the company. Dr. Bready served as CEO ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... June 23, 2016   Boston Biomedical , ... compounds designed to target cancer stemness pathways, announced ... granted Orphan Drug Designation from the U.S. Food ... gastric cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin ... to inhibit cancer stemness pathways by targeting STAT3, ...
(Date:6/23/2016)... ... June 23, 2016 , ... Charm Sciences, Inc. is ... has received AOAC Research Institute approval 061601. , “This is another AOAC-RI approval ... Bob Salter, Vice President of Regulatory and Industrial Affairs. “The Peel Plate methods ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... announced the launch of the Supplyframe Design Lab . Located in Pasadena, ... explore the future of how hardware projects are designed, built and brought to ...
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a ... discoveries to the medical community, has closed its Series ... Matthew Nunez . "We have received a ... the capital we need to meet our current goals," ... provide us the runway to complete validation on the ...
Breaking Biology Technology: