Friday, July 09, 2010

Scientists make an AIDS breakthrough

But unlikely to be of use for long, sadly. Knocking out 90% of the HIV strains is not enough. It will just lead to the resistant 10% multiplying

US researchers have discovered two powerful antibodies that neutralise more than 90 per cent of all known strains of the HIV virus in the lab, new research released today showed.

NIH-led scientists discovered the antibodies known as VRCO1 and VRCO2 that prevent most HIV strains from infecting human cells. The find is a potential breakthrough for advancing HIV vaccine design, and antibody therapy for other diseases.

The authors, whose work is published in the July 9 issue of Science, also were able to demonstrate how one of these disease-fighting proteins gets the job done.

"The discovery of these exceptionally broadly neutralising antibodies to HIV and the structural analysis that explains how they work are exciting advances that will accelerate our efforts to find a preventive HIV vaccine for global use," said Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health.

"In addition, the technique the teams used to find the new antibodies represents a novel strategy that could be applied to vaccine design for many other infectious diseases," Dr Fauci said.

The team of virologists found that the two antibodies were produced naturally and found in the blood of HIV-positive people.

They were able to isolate these antibodies using a new molecular device they developed. It zeroes in on specific cells that make antibodies against HIV. The device is an HIV protein scientists modified to react only with antibodies specific to the site where the virus binds to cells it infects.

Leading two research teams were NIAID scientists Peter Kwong, PhD, John Mascola, MD, and Gary Nabel, MD, PhD.

"We have used our knowledge of the structure of a virus - in this case, the outer surface of HIV - to refine molecular tools that pinpoint the vulnerable spot on the virus and guide us to antibodies that attach to this spot, blocking the virus from infecting cells," Dr Nabel said.

Dr Mascola said that: "the antibodies attach to a virtually unchanging part of the virus, and this explains why they can neutralise such an extraordinary range of HIV strains."


The one-a-day pill that could finally halt Alzheimer's?

Sounds hopeful but demonstrated on rodents only so far

A single daily pill that stops Alzheimer's in its tracks is being developed by scientists. The drug, discovered by sheer luck according to researchers, stops brain cells from dying, boosting their numbers and sharpening memory. Given early enough, it could prevent sufferers from reaching the devastating final stages of the disease, in which they lose the ability to walk, talk and even swallow. Some experts believe it could even be a cure.

Alzheimer's and other forms of dementia blight the lives of more than 800,000 Britons, and the number of cases is expected to double within a generation.

With the death of brain cells at the core of Alzheimer's, the breakthrough brings fresh hope.

U.S. researchers found the drug after testing more than 1,000 chemicals on mice. Dr Steven McKnight said: 'We really didn't know if the screen would turn up a favourable compound or not. It was blind luck.' In tests, the drug, known only as P7C3, boosted the production of cells in a part of the brain critical to memory.

Dr McKnight, of the University of Texas Southwestern, said: 'These mice are bad at making new neurons. The question was, "Can you fix that?" And the answer to that was "yes".' Not only did the new brain cells form, but they also worked properly, the journal Cell reports.

In other experiments, the drug improved memory in ageing rats, making it easier for them to find their way through a maze. Further research showed that a derivative of the compound, called A20, had an even bigger impact on the brain.

Dr McKnight and colleague Dr Andrew Pieper are still trying to find out how the drug works.

Much of the research into Alzheimer's focuses on breaking down the sticky protein that clogs the brain, damaging and killing cells. Most existing drugs would not be a cure as they cannot repair dead tissue.

But P7C3 could offer an exciting alternative as it chaperones neurons key to memory through to adulthood, greatly boosting their numbers.

Two drugs that work in this way are already being tested on patients. One, an anti-histamine called Dimebon, had encouraging early results but has failed to live up to its promise.

Dr McKnight, who received a 'pioneer award' designed to fund unusual research, said last night: 'If this pans out, it will be the most useful contribution of my career.'

It appears to prevent a process called apoptosis, which causes cells, including many newly-formed brain cells, to self-destruct.

It also seems to give a boost to the mitochondria, the tiny batteries that power cells.

The research team hope the chemical can be turned into a once-a-day pill. Those with multiple sclerosis, Huntington's disease and schizophrenia might also benefit. Dr McKnight said: 'The neuroprotective compound P7C3 holds special promise because of its medicationfriendly properties.

'It can be taken orally, crosses the blood-brain barrier with long-lasting effects, and is safely tolerated by mice during many stages of development.'

The blood-brain barrier is a biological 'wall' designed to prevent potentially harmful substances entering the brain.

Thomas Insel, director of the U.S. body that funded the work, the National Institute of Mental Health, said: 'This striking demonstration of a treatment that stems age-related cognitive decline in living animals points the way to potential development of the first cures that will address the core illness process in Alzheimer's disease.'


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