Written By: Nirmalya Dutta | Updated : March 10, 2014 11:12 PM IST
A research team has found how the immune system makes a powerful antibody that blocks HIV infection of cells by targeting a site on the virus called V1V2.
Analyses of the results of a clinical trial of the only experimental HIV vaccine to date to have modest success in people suggest that antibodies to sites within V1V2 were protective.
The new findings point the way toward a potentially more effective vaccine that would generate V1V2-directed HIV neutralizing antibodies.
The study led by scientists from the National Institute of Allergy and Infectious Diseases (NIAID) began by identifying an HIV-infected volunteer in the CAPRISA cohort who naturally developed V1V2-directed HIV neutralizing antibodies, named CAP256-VRC26, after several months of infection. (Read: Is there an anti-HIV drug on its way?)
Using techniques similar to those employed in an earlier study of HIV-antibody co-evolution, the researchers analyzed blood samples donated by the volunteer between 15 weeks and 4 years after becoming infected.
Notably, the study revealed that after relatively few mutations, even the early intermediates of CAP256-VRC26 can neutralize a significant proportion of known HIV strains.This enabled the scientists to determine the genetic make-up of the original form of the antibody; to identify and define the structures of a number of the intermediate forms taken as the antibody mutated toward its fullest breadth and potency; and to describe the interplay between virus and antibody that fostered the maturation of CAP256-VRC26 to its final, most powerful HIV-fighting form.
This improves the chances that a V1V2-directed HIV vaccine developed based on the new findings would be effective, according to the scientists, who have begun work on a set of vaccine components designed to elicit V1V2 neutralizing antibodies and guide their maturation.
Other possible HIV cures
Should we be optimistic or cautious? This isn't the first time that we've been presented with tales that an HIV cure is on its way. The most famous of them are:
The Berlin Patient Case Leukaemia
For a long time researchers believed there was no cure. Even five years ago, a scientist who wanted to work on HIV cure research was laughed at. But all that changed with Timothy Brown aka the Berlin Patient. Brown an HIV-positive man who developed leukaemia. After first-line cancer treatments failed, a bone marrow transplant procedure was done. Two transplants later, not only was his leukaemia in remission, his immune system actually managed to ward off HIV. Brown no longer takes antiretroviral drugs or tests positive for HIV. Essentially, he was cured. Read more
Bee venom to cure HIV?
A study suggested that bee venom might have the potency to kill the human immunodeficiency virus (HIV). Researchers at the Washington University School of Medicine had demonstrated that a toxin called melittin which is found in bee venom is the reason for this. The researchers used nanoparticle technology to target the virus. Particles smaller than HIV were infused with bee venom and since HIV cells are smaller than normal body cells the nanoparticles only targeted HIV.
'Melittin on the nanoparticles fuses with the viral envelope,' said research instructor Joshua L. Hood, MD, PhD. 'The melittin forms little pore-like attack complexes and ruptures the envelope, stripping it off the virus.' Adding, 'We are attacking an inherent physical property of HIV. Theoretically, there isn't any way for the virus to adapt to that. The virus has to have a protective coat, a double-layered membrane that covers the virus.'
Stem cell therapy to overcome HIV?
In a path-breaking breakthrough two American were believed to have overcome HIV after undergoing stem-cell therapy! The news has met with widespread elation with experts believing that a cure might be on the cards. Doctors from the Brigham and Women's Hospital in Boston announced on Wednesday night that two previously HIV-positive patients no longer had detectable virus levels in their blood or tissue after having bone marrow stem-cell transplants to treat cancer between two and four years ago, the Age reported. (Read more )
Aggressive antiretroviral treatment the Mississippi baby case
There were reports in March 2013 of a toddler who was completely cured of the virus after being born of it. She has been cured of the disease after following an aggressive regime of drugs. This was the second documented case of a person being completely cured of the virus after an adult known as the Berlin Patient was cured as a result of bone-marrow transplant. This startling piece of information was discovered when the baby's mother stopped treatment and doctors lost track of the baby who was given a bout of heavy drugs (current procedure suggests only a modest daily dose of antiretroviral treatment) about 30 hours after she was born at a rural Mississippi hospital, doctors said at a medical meeting in Atlanta. However, a doctor poured cold water on cold water on what was termed 'the greatest medical breakthrough of the century'.
In his piece, Dr Siedner pointed out in his column, exposure to HIV doesn't mean that the baby will have HIV. 'We will likely never know if those cells were from the child or maternal cell that has been transmitted during pregnancy or birth.' When a child is born, he or she has some maternal cells in his system so it's impossible to tell whether the child actually had HIV or not, or the tests detected the maternal HIV positive cells.
The MX2 gene
According to a study published in the journal Nature, scientists have discovered a new gene which can inhibit the HIV virus from spreading after it has entered the body. The study was led by Dr Caroline Goujon and Professor Mike Malim at the Department of Infectious Diseases, King's College London. It was conducted by introducing the virus to two separate lines of human cells. On one line, they introduced the MX2 gene along with the virus, while on the other they didn't. The line on which the MX2 gene was introduced, it was seen that the virus had stopped replicating. (Read more.)
With inputs from ANI
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