New insights into how certain slow progressers control HIV infection

September 19, 2012

People with a rare genetic trait who are infected with HIV progress more slowly to AIDS than others. But even within this group, there are wide variations in time to progression. A new study illustrates in detail how the immune system fights the virus in those subjects who progress more slowly. The research, which could prove useful to efforts to develop a vaccine against HIV, is published in the September Journal of Virology.

Absent , most of those infected with HIV progress to AIDS within a decade. But 5-15 percent remain symptom free for years even without therapy. A portion of these people maintain high CD4+T immune cell counts, along with low levels of virus for several years. Many of these people possess the afore-mentioned rare , the awkwardly-named HLA-B*5701 allele (an allele is one possible version of a gene), and their time of progression can range from around six years to well beyond ten years.

The researchers, led by Melissa M. Norstrom and Annika K. Karlsson of the Karolinska Institute, Stockholm, Sweden, and Marco Salemi of the University of Florida, Gainesville, studied evolution of HIV, and immune responses in six untreated HIV-infected patients carrying the protective genetic trait, following them from soon after infection, for seven years. In particular, they studied a set of molecules that are produced by called CD8+T cells, which are involved in combating .

"We found that subjects with lower risk of progressing to AIDS were characterized by a higher proportion of CD8+T cells that produced several of these molecules simultaneously," says Norstrom. They also found that in these patients, the virus evolved much more slowly. Further, viral mutations, which normally occur somewhat haphazardly during , appeared to happen in a specific order, which the researchers postulate resulted from selective constraints exerted by the immune system.

"Understanding the mechanisms associated with slower progression to AIDS may ultimately provide new insights on how to cure HIV, or even how to develop a protective vaccine," says Salemi.

The research had a serendipitous origin, when Norstrom and Salemi met at a workshop on viral evolution, says Salemi. "The exciting discussions during that scientific meeting led to establishment of a successful multidisciplinary collaboration, which included experts in immunology and viral evolution, as well as with Dr. [Frederick M.] Hecht at the University of California, San Francisco, who provided samples from patients carrying this unique genetic trait."

Explore further: HIV-2 infection inhibits HIV-1 disease progression

More information: M.M. Norstrom, M. Buggert, J. Tauriainen, W. Hartogensis, M.C. Prosperi, M.A. Wallet, F.M. Hecht, M. Salemi, and A.C. Karlsson, 2012. Combination of immune and viral factors distinguishes low-risk versus high-risk HIV-1 disease progression in HLA-B*5701 Subjects. J. Virol. 86:9802-9816.

Related Stories

HIV-2 infection inhibits HIV-1 disease progression

July 19, 2012
(HealthDay) -- While many people don't know it, there's more than one kind of AIDS virus. Besides the HIV-1 strain that's common throughout the world, a type known as HIV-2 is found in some parts of Africa. Now, a new study ...

Study finds HIV-specific CD4 cells that control viral levels

February 29, 2012
A subpopulation of the immune cells targeted by HIV may play an important role in controlling viral loads after initial infection, potentially helping to determine how quickly infection will progress. In the February 29 issue ...

Natural HIV control may rely on sequence of T cell receptor protein

June 11, 2012
The rare ability of some individuals to control HIV infection with their immune system alone appears to depend – at least partially – on specific qualities of the immune system's killer T cells and not on how many ...

Recommended for you

Three-in-one antibody protects monkeys from HIV-like virus

September 20, 2017
A three-pronged antibody made in the laboratory protected monkeys from infection with two strains of SHIV, a monkey form of HIV, better than individual natural antibodies from which the engineered antibody is derived, researchers ...

Fighting HIV on multiple fronts might lead to vaccine

September 20, 2017
A combination antibody strategy could be the key to halting the spread of HIV, according to results from two promising animal studies.

HIV-AIDS: Following your gut

September 18, 2017
Researchers at the University of Montreal Hospital Research Centre (CRCHUM) have discovered a way to slow viral replication in the gastrointestinal tract of people infected by HIV-AIDS.

Study finds cutbacks in foreign aid for HIV treatment would cause great harm

August 30, 2017
Proposed reductions in U.S. foreign aid would have a devastating impact on HIV treatment and prevention programs in countries receiving such aid, an international team of investigators reports. In their paper published online ...

Cancer drug can reactivate HIV

August 24, 2017
People living with HIV must take a combination of three or more different drugs every day for the rest of their lives. Unfortunately, by following this strict treatment plan, they can suffer from side effects ranging from ...

New injectable antiretroviral treatment proved to be as effective as standard oral therapy

August 3, 2017
Intramuscularly administered antiretroviral therapy (ART) may be as effective for HIV treatment as current oral therapies. This is the main conclusion of a Phase II clinical trial carried out by 50 research centers around ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.