Transmission of HIV: Study spotlights virus that starts infection

November 7, 2011 in HIV & AIDS

(Medical Xpress) -- When HIV is transmitted from one person to another, the virus faces a genetic "bottleneck." This means that usually during heterosexual transmission, only one virus out of a swarm of frequently mutating viruses establishes the new infection.

Now Emory Vaccine Center researchers have shown that the that starts an individual’s new differs markedly from the dominant strains in his or her partner’s genital tract. This suggests that the process of transmission favors some viral variants, and the bottleneck effect doesn’t arise simply by chance or through what types of virus flourish better in the genital tract.

The results are published online this week in Proceedings of the National Academy of Sciences, Early Edition.

“If the success of the establishing virus came only by chance, most of the time it would be one of the viruses that is most abundant in the donor’s genital tract. But we don’t see that,” says senior author Eric Hunter, PhD, professor of pathology and laboratory medicine at Emory University School of Medicine. “What we see suggests that transmission is selecting for certain viruses. The virus establishing the infection is a single variant, but that variant is different for each transmission event.”

The first author of the paper is senior scientist Debrah Boeras, PhD, now at the Centers for Disease Control and Prevention. Dr. Hunter is co-director of Emory’s Center for AIDS Research and a Georgia Research Alliance Eminent Scholar. Emory co-authors include Susan Allen, MD, MPH, professor of pathology and laboratory medicine and Cynthia Derdeyn, PhD, associate professor of pathology and laboratory medicine in Emory School of Medicine. Collaborators from Los Alamos National Laboratory contributed to the paper.

Access to patient samples came through collaboration with co-investigators and volunteers at Emory’s HIV research programs in Rwanda and Zambia. The researchers obtained vaginal swabs, semen, and blood samples from eight consenting heterosexual couples in Rwanda and Zambia at the time the newly infected partners were diagnosed as HIV-positive. Of the eight instances of infection, six involved female-to-male transmission.

Boeras and her colleagues determined the DNA sequences for the viruses’ env gene, which encodes a protein forming the outer coat of the virus. They found that a single genetic variant in the genital tracts of the donor established an infection in the recipient.

Hunter emphasized that the paper’s results are the starting point for a detailed study of the distinguishing features of viruses that initiate infection.

“There is clearly a lot of work still to do,” he says. The big challenge now is to understand the features of the viruses that start an infection, and target them with microbicides or vaccines. It could help us be much smarter in how we try to protect people.”

Other studies have already shown that “founder” viruses have Env proteins that are more compact and have fewer sites that can be modified with sugars, which may affect how these viruses interact with genital tissue in the uninfected partner.

This topic is the focus of current research in the Hunter laboratory, and their results could inform design of a still-elusive vaccine.

More information: D.I. Boeras et al. Role of donor genital tract HIV-1 diversity in the transmission bottleneck. PNAS Early Edition (2011)

Provided by Emory University search and more info website

3 /5 (1 vote)  

Rank 3 /5 (1 vote)
Relevant PhysicsForums posts

More news stories

Integrating mental health care into HIV care

The integration of mental health interventions into HIV prevention and treatment platforms can reduce the opportunity costs of care and improve treatment outcomes, argues a new Policy Forum article published in this week's ...

HIV & AIDS created 7 hours ago | popularity not rated yet | comments 0

After a decade, global AIDS program looks ahead

(AP)—The decade-old law that transformed the battle against HIV and AIDS in developing countries is at a crossroads. The dream of future generations freed from the epidemic is running up against an era ...

HIV & AIDS created 20 hours ago | popularity not rated yet | comments 0

'Gap' for HIV vaccine efforts after latest setback

The hunt for an HIV vaccine has gobbled up $8 billion in the past decade, and the failure of the most recent efficacy trial has delivered yet another setback to 26 years of efforts.

HIV & AIDS created May 19, 2013 | popularity 5 / 5 (1) | comments 0

AIDS science at 30: 'Cure' now part of lexicon

Big names in medicine are set to give an upbeat assessment of the war on AIDS on Tuesday, 30 years after French researchers identified the virus that causes the disease.

HIV & AIDS created May 18, 2013 | popularity 5 / 5 (2) | comments 0

Peer-referral programs can increase HIV-testing in emergency departments

Researchers at the University of Cincinnati (UC) have found that incorporating a peer-referral program for HIV testing into emergency departments can reach new groups of high-risk patients and brings more patients into the ...

HIV & AIDS created May 17, 2013 | popularity not rated yet | comments 0


If you can remember it, you can remember it wrong

(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...

B vitamins could delay dementia

(Medical Xpress)—Despite spending billions of dollars on research and development, drug companies have been unable to come up with effective treatments for dementia and Alzheimer's Disease (AD). Now, A. ...

New sleeping pill poised to hit US markets

An experimental sleeping pill from US drug company Merck is effective at helping people fall and stay asleep, according to reviewers at the US Food and Drug Administration, which could soon approve the new drug.

Reducing caloric intake delays nerve cell loss

Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May ...

Insight into the dazzling impact of insulin in cells

Australian scientists have charted the path of insulin action in cells in precise detail like never before. This provides a comprehensive blueprint for understanding what goes wrong in diabetes.

Antidepressant reduces stress-induced heart condition

A drug commonly used to treat depression and anxiety may improve a stress-related heart condition in people with stable coronary heart disease, according to researchers at Duke Medicine.