I want to be very clear here: this is a preliminary report and it's very early days even to think in terms of an HIV vaccine. Still, any sign of hope is worth noting. Agence France Presse reported yesterday afternoon that French researchers at the Institut Pasteur and elsewhere
"had stimulated antibodies which dramatically barred the AIDS virus from infecting human immune cells." (I am cross-posting this from my blog,
Musing's musings.)
This is not an HIV vaccine. As the headline to the linked story notes, however, this preliminary
in vitro success is "good news" for the continuing quest to find such a vaccine.
Unlike previous efforts, which were focused on raising antibodies to specific proteins from the virus' protein coat, the French researchers targeted only a small portion of a surface protein. They claim this protein region is common "across the range of HIV types." That would be important in any potential vaccine, because one hypothesis for why HIV has been such a huge health catastrophe is the existence of multiple strains of the virus with few similarities. (Another is the virus' ability to mutate quickly, which would limit the effectiveness of specific remedies.) According to a statement released yesterday:
This area is called CBD1 and is part of the gp41 protein. CBD1 binds to a protein in the T-lymphocyte immune cell called caveolin-1, thus helping the AIDS virus to dock to and infiltrate its target.
The researchers synthesised a chain of peptides -- the building blocks of proteins -- corresponding to CBD1 and immunised rabbits with it.
In lab-dish experiments in which blood taken from the immunised rabbits was exposed to human T-cells and the virus, it proved to be a remarkable shield against a range of sub-types of HIV-1, the commoner and more vicious form of the two big strains of the virus.
"The anti-CBD1 antibodies work in two ways," the press statement said. "Firstly, they inhibit cellular infection by HIV, and secondly, among cells that are already infected, they lead to the production of defective viruses (which) are unable to infect other cells."
The vaccine is only experimental and has not been applied to any human volunteers to see whether it is safe or effective.
That these antibodies appear to have dual effect is very promising. The goal of any vaccine is to prevent the immunized person from contracting the disease in question. That may or may not be possible with HIV because of the nature of the virus. That this protein fragment could also cause an infected person's cells to pump out compromised viruses that would at least serve to limit the possibility of subsequent infections offers another line of defense against the AIDS pandemic.
Since I was a guinea pig for Vaxgen's unsuccessful bivalent vaccine in clinical trials from 1999-2002 I might not be eligible to volunteer for this one. But if I can, I'll seriously consider it. The stakes are too high, and even though I only lost two good friends to AIDS, that's still two too many. Consider it my tribute to them.
In any event, I'll be praying and sending good thoughts for the success of this research. I'd love to be able to say I lived through the AIDS pandemic, from the time of its discovery until we licked the sumbitch. It's a tremendously sad reality that more than 20 million people worldwide can't say the same--and the toll rises with each passing day.
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