Posted on 09/05/2009 8:36:44 PM PDT by neverdem
A team of scientists in the US has discovered two new antibodies that could lead to an HIV vaccine. Researchers from the Scripps Institute in California, the International Aids Vaccine Initiative (IAVI) and US-based biotech companies Theraclone Sciences and Monogram Biosciences discovered these two broadly neutralising antibodies using high-throughput screening of serum from patients infected with HIV.
When people are first infected with HIV, they produce antibodies that are specific to the infected strain, but a few years later some start to make antibodies active against other strains of the virus - known as broadly neutralising antibodies. 'There is a huge variability in the virus, so vaccination has to induce antibodies that are broad,' explains Dennis Burton, scientific director of the IAVI neutralising antibody centre at Scripps. 'Only four such antibodies have been isolated in the past, and none in the past decade.'
The new antibodies are important as they provide a big clue for future vaccine design. They are directed at the viral spike that HIV uses to infect cells, and which produces the glycoproteins gp120 and gp41. These are highly variable and evolved to prevent immune attack, but the antibodies target a part of gp120 that does not change. 'As well as being broadly neutralising, they are also more potent,' Burton says. 'This is good as the concentration that would have to be induced by a vaccine is lower. They bring a vaccine more within reach.'
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Approximately 33 million people worldwide are infected with the HIV virus (above)
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Serum from nearly 2000 HIV-infected donors from Thailand, Australia, the UK, US and several sub-Saharan African countries was screened for broad and potent neutralising activity, covering about 160 different forms of HIV; about three-quarters of these strains were neutralised with the newly discovered antibodies.
'We don't expect one antibody to neutralise everything, but we hope we can design vaccine candidates that will induce not just one but several of these antibodies, and that will slowly get us up to 100 per cent protection,' says Burton.
A troubled past
The search for a vaccine against HIV has been dogged by failure. Two years ago, Merck's vaccine candidate V520 failed in Phase II trials when it appeared to leave subjects more susceptible to infection, not less. Another vaccine which worked in the same way - inducing an immune response in the body's own T-cells - was also canned last summer by the US National Institutes of Health.
Burton is now optimistic about the possibility of developing an effective HIV vaccine. 'I'm more enthusiastic about this than anything that's happened for quite some time,' he says. 'I worried that we had these four antibodies, and their potency was not terrific. But given the potency of the new antibodies I think we are on much better ground. It's still a very long way to go, but it's a very positive signal.'
'It's interesting that they have identified new antibodies that are not cross-reactive with the currently known antibodies,' says Steve Patterson of Imperial College medical school's division of investigative science. 'I think the general view is that we need both T-cells and antibodies to give protection, and with the failure of the Merck trial there has been renewed interest in the antibody side. There seems to be a hierarchy of development of the immune response that strain-specific antibodies come up first, followed by broadly neutralising ones later on. The trick will be to induce immune responses that are usually seen later on in the disease.'
L M Walker et al, Science, 2009, DOI: 10.1126/science.1178746
This bit of news should titillate all the “alternative lifestyle” aficionados.
Those evil profit dollars hard at work hu? I guess with obamacare the cure will never be finished.
Fascinating. This is about a great deal more than HIV. The mechanisms for the broader expression of the immune response are a little murky but it appears that over time they can account for viral variation if not quite catch up to it. If the infectious agent is held more or less in stasis (as such treatments as protease inhibitors are designed to do) then what happens after the body does catch up? I’ll be watching this one - thanks for posting.
Hmmm. Apparently, 25 million of them live in sub-Saharan Africa.
18 million have died in the sub Saharan Africa, over what I gather is the last 10 years, 3 million of which were children. That means 15 million children have been orphaned because of the deaths of 15 million of their parents.
The population Of Africa is 922 million (as of 2005) which means 2.7% of the population have aids. and about 1.8% of the population have died of aids over the past ten years. or about .2% per year.
Something just doesn't sound right here. I think it has to do with the tens of billions of dollars that seem to vanish into thin air every year.
Then again, these UN-NGO’s handle most of that money, and special jeeps, French cuisine, 5 star hotels, fat salaries all cost money. It’s vital that they spend it gathering data, so they know how much money they’ll need in the future from member nations to actually begin treating aids.
Excellent read.
Thanks!
Thanks for the link. Are you related to Alan Gura from D.C. v. Heller?
I’d rather them come out with a cancer vaccine.
I used to say the same thing. Then something occured to me. What if AIDS goes airborne?
Since most people don’t even know they have it until years later, most the world-wide population would end up infected before anyone knew anything about it.
Read up on how viruses mutate, its not at all unlikely for something like this to happen.
Not fear, there is Hope
Hope and grant money............ that’s the ticket
What they SHOULD take away from this is that there are many and rapidly changing forms of the HIV virus and that it is going to be a horrendous difficulty to ever control it and that it is likely there never be something such as a vaccine to protect against it.
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