New HIV vaccine will be tested in South Africa

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An experimental AIDS vaccine that's worked better than anything else tried so far is going to be tested in South Africa, U.S. health officials said Wednesday.

They've tweaked the vaccine, which prevented infection by just about a third, and hope it will work better in this trial.
An experimental AIDS vaccine that's worked better than anything else tried so far is going to be tested in South Africa, U.S. health officials said Wednesday.

They've tweaked the vaccine, which prevented infection by just about a third, and hope it will work better in this trial.

Why Isn't There an AIDS Vaccine Yet? 0:42
"For the first time in seven years, the scientific community is embarking on a large-scale clinical trial of an HIV vaccine, the product of years of study and experimentation," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID).

NIAID is part of the National Institutes of Health and a co-funder of the trial.

"A safe and effective HIV vaccine could help bring about a durable end to the HIV/AIDS pandemic and is particularly needed in southern Africa, where HIV is more pervasive than anywhere else in the world."

There's no cure for the human immunodeficiency virus (HIV) that causes AIDS, but cocktails of antiviral drugs can keep it under control — and if people take some of the same drugs they can protect themselves against infection.

That approach, called pre-exposure prophylaxis or PrEP can reduce the risk of catching HIV by 90 percent if people use it consistently. But it's not cheap, and studies suggest it could be difficult for people in developing countries to stick to, if they could even get the drugs.

Most experts agree the best way to fight the virus — which infects 35 million people globally and which kills 1.2 million a year — would be to have a good vaccine.

"While we are making encouraging progress — new HIV infections have fallen by 35 percent globally since 2000 — the development of a safe and effective HIV vaccine would be the ultimate game-changer," Fauci wrote in a blog post.

The experimental vaccine being tested in based on a U.S. military vaccine called RV144 that protected 31 percent of volunteers in Thailand in 2009.

"The design and schedule of the RV144 vaccine regimen have been adjusted to try to increase the magnitude and duration of vaccine-elicited immune responses," NIAID said. "The trial is slated to begin in November 2016, pending regulatory approval."
 
hat's the Latest Development?

Researchers at Oregon Health and Science University hope to begin testing an HIV vaccine on humans in just a few years, thanks to an innovative approach which helps the body's immune system target the evasive virus. "The researchers found that cytomegalovirus or CMV, a common virus already carried by a large percentage of the population, may hold the key. Their studies in the non-human primate model of HIV, called SIV, found that a modified version of CMV engineered to express SIV proteins generates SIV-specific T cells that recognize three-fold as many SIV peptides as T cell generated by conventional vaccines and SIV itself."

What's the Big Idea?

To create a vaccine against HIV, scientists need to activate the body's immune system against the disease, specifically so-called T cells which work as sentries to detect and destroy virus-infected cells. T cells, however, are frugal in the number of different viral peptides they can recognize at one time. "This is a problem for control of HIV, which is able to able change its peptides and thus escape T cells responses that do not target the relatively few functionally critical peptides that can't change without debilitating the virus. In the vast majority of HIV infections, the few viral peptides recognized by T cells are not the vulnerable ones, and the virus escapes."

Photo credit: Shutterstock.com

Read it at Science Daily
 
HIV update - 11th May 2016
HIV transmission and antiretroviral therapy
Antiretroviral treatment greatly reduces the risk of transmitting HIV. Several very large studies have now shown that people with undetectable viral load do not pass on HIV to their sexual partners.However, there is still a possibility that HIV might be passed on during the period between starting treatment and viral load becoming detectable, which may take up to six months, or if viral load rebounds due to treatment failure.

A review of a large PrEP study conducted in couples where one partner had HIV and the other did not, has shown that when the partners with HIV became eligible to start antiretroviral treatment for their own health, there was still a risk that HIV could be passed on before they reached an undetectable viral load.

The study of 1592 couples found that three infections took place during the first six months on treatment, all from women to their male partners. The study investigators were not able to measure viral load each month or test partners each month. In one case infection almost certainly took place either just before or around the time that treatment was started.

In the other two cases, transmission occurred no later than two and five months after the HIV-positive partner started treatment. In the former case viral load was not measured for the first time until after seroconversion was detected. In the latter case viral load had been measured at three months and had been found to be detectable. Plasma viral load was measured at 872 copies/ml at this time, which is below the level found to be associated with male-to-female transmission in a previous large study.
 
Researchers may be one step closer to curing HIV
May 17, 2016

Scientists from KU Leuven, Belgium, present a new therapeutic approach that may make it possible for HIV patients to (temporarily) stop their medication. The findings shed a completely new light on the search for a cure for HIV.

Existing antiviral inhibitors can suppress the replication of the HIV virus, but they cannot fully remove it from the human body. As a result, HIV patients have to take inhibitors for the rest of their lives. HIV researchers worldwide are currently developing new methods to eliminate the virus.

The HIV virus uses the cellular protein LEDGF as a kind of grappling-hook to attach itself to specific locations in our genetic material. Once its DNA is inside the cells of its human host, the virus can multiply and make the patient sick.

In 2010, the research team of KU Leuven Professor Zeger Debyser developed inhibitors—called LEDGINs—that block the 'grappling-hook'. As a result, the virus cannot attach itself to its preferred locations in our DNA.

Doctoral student Lenard Vranckx has now discovered that, when treated with LEDGINs, the HIV virus settles elsewhere in our DNA, in locations where it cannot multiply. Lenard Vranckx explains: "We've shown that a treatment with LEDGINs not only inhibits the integration of the HIV virus, but also ensures that the virus doesn't multiply once the treatment is stopped."

"This discovery paves the way for new clinical studies with LEDGINs," Professor Debyser continues. "We don't know whether this approach will lead to a final cure for HIV, but even a scenario that allows patients to stop their medication for a while is an important step in the right direction."

However, the researchers remain cautious: "We don't want to give anyone false hope. Our discovery is based on cell cultures. The findings still need to be tested in mice and in clinical studies. That's why a potential treatment based on the discovery is still years in the future," says Professor Debyser. "But now, we already know the direction of our future research."

Explore further: Targeting HIV 'reservoir' could be first step to understanding how to cure the disease

More information: Lenard S. Vranckx et al, LEDGIN-mediated Inhibition of Integrase–LEDGF/p75 Interaction Reduces Reactivation of Residual Latent HIV, EBioMedicine (2016). DOI: 10.1016/j.ebiom.2016.04.039

Provided by: KU Leuven
 
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