HIV infection stems from few viruses

May 16, 2008

A new study reveals the genetic identity of human immunodeficiency virus (HIV), the version responsible for sexual transmission, in unprecedented detail.

The finding provides important clues in the ongoing search for an effective HIV/AIDS vaccine, said researchers at the University of Alabama at Birmingham (UAB). The UAB team found that among billions of HIV variants only a few lead to sexual transmission.

Earlier studies have shown that a ‘bottleneck’ effect occurs where few versions of the virus lead to infection while many variants are present in the blood. The UAB study is the first to use genetic analysis and mathematical modeling to identify precisely those viruses responsible for HIV transmission.

George M. Shaw, M.D., Ph.D., professor in the UAB departments of Medicine and Microbiology and senior author on the report, said the research sheds new light on potential vulnerabilities in the virus at a time when science, medicine and society are still reeling from the failure of a major HIV vaccine clinical trial.

“We can now identify unambiguously those viruses that are responsible for sexual transmission of HIV-1. For the first time we can see clearly the face of the enemy,” said Shaw, a project leader with the Center for HIV/AIDS Vaccine Immunology. The center is a National Institutes of Health-sponsored consortium of researchers at UAB, Harvard Medical School in Boston, Oxford University in England, the University of North Carolina in Chapel Hill and Duke University in Durham, N.C.

The new HIV-1 findings are published online in the Proceedings of the National Academy of Sciences.

The new study was performed by sequencing many copies of the HIV envelope gene present in the viruses taken from 102 recently infected patients. The envelope gene encodes for a protein called Env that forms part of the outer covering of the virus, and is responsible for its infectiousness.

The researchers then used sophisticated mathematical models of HIV replication and genetic change to identify the virus or viruses responsible for transmission. In 80 percent of the newly infected patients, a single virus caused transmission, though each virus was different in each patient. In the other 20 percent of patients, two to five unique viruses caused transmission.

“Previously, researchers employed inexact methodologies that prevented precise identification of the virus that initiated infection,” said Brandon Keele, Ph.D., an instructor in UAB’s Department of Medicine and lead study investigator. “Our findings allow us to identify not only the transmitted virus, but also viruses that evolve from it.”

The UAB team said their work would lead to new research on how different HIV genes and proteins work together to make a virus biologically fit for transmission and for growth in the face of mounting immunity.

Statistics show that while the worldwide percentage of people infected with HIV has leveled off, the total number HIV cases is rising. In 2007, 33.2 million people were estimated to be living with HIV, 2.5 million people became newly infected and 2.1 million people died from AIDS, according to the Joint United Nations Programme on HIV/AIDS (UNAIDS) and the World Health Organization.

Source: University of Alabama at Birmingham

4.6 /5 (16 votes)  

Rank 4.6 /5 (16 votes)
Tags

Relevant PhysicsForums posts

More news stories

Discovery paves way for salmonella vaccine

(Medical Xpress) -- An international research team led by a University of California, Davis, immunologist has taken an important step toward an effective vaccine against salmonella, a group of increasingly antibiotic-resistant ...

Medicine & Health / Research

created 12 minutes ago | popularity 5 / 5 (2) | comments 0 | with audio podcast

First-of-its-kind stem cell study re-grows healthy heart muscle in heart attack patients

Results from a Cedars-Sinai Heart Institute clinical trial show that treating heart attack patients with an infusion of their own heart-derived cells helps damaged hearts re-grow healthy muscle.

Medicine & Health / Cardiology

created 18 minutes ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

Ovarian cancer arises in fallopian tube of knockout mice

(Medical Xpress) -- The most deadly form of "ovarian" cancer arises in the fallopian tubes – not the ovaries – of knockout mice that lack two genes associated with the disease, said researchers led by Baylor College ...

Medicine & Health / Cancer

created 13 minutes ago | popularity not rated yet | comments 0 | with audio podcast

Smoking bans lead to less, not more, smoking at home: study

Smoking bans in public/workplaces don't drive smokers to light up more at home, suggests a study of four European countries with smoke free legislation, published online in Tobacco Control.

Medicine & Health / Health

created 18 minutes ago | popularity not rated yet | comments 0

UK cases of progressive sight loss condition set to rise a third by 2020

New cases of the progressive sight loss condition, known as age-related macular degeneration, or AMD for short, are set to rise by a third in the UK over the next decade, reveals research published online in the British Jo ...

Medicine & Health / Diseases

created 17 minutes ago | popularity not rated yet | comments 0


Scientists discover reason for Mt. Hood's non-explosive nature

(PhysOrg.com) -- For a half-million years, Mount Hood has towered over the landscape, but unlike some of its cousins in Oregon’s Cascade Mountains and many other volcanoes around the Pacific “Rim ...

Time of year important in projections of climate change effects on ecosystems

(PhysOrg.com) -- Does it matter whether long periods of hot weather, such as last year's heat wave that gripped the U.S. Midwest, happen in June or July, August or September?

Medical school link to wide variations in pass rate for specialist exam

Wide variations in doctors' pass rates, for a professional exam that is essential for one type of specialty training, seem to be linked to the particular medical school where the student graduated, indicates research published ...

Missing dark matter located: Intergalactic space is filled with dark matter

Researchers at the University of Tokyo’s Institute for the Physics and Mathematics of the Universe (IPMU) and Nagoya University used large-scale computer simulations and recent observational data of gravitational ...

Plants use circadian rhythms to prepare for battle with insects

In a study of the molecular underpinnings of plants' pest resistance, Rice University biologists have shown that plants both anticipate daytime raids by hungry insects and make sophisticated preparations to ...

Sensing self and non-self: New research into immune tolerance

At the most basic level, the immune system must distinguish self from non-self, that is, it must discriminate between the molecular signatures of invading pathogens (non-self antigens) and cellular constituents that usually ...