Scientists at the Scripps Research Institute in Florida have shown that a lab-made molecule can provide more protective power against HIV than anything produced naturally currently available.
Since HIV emerged in the 1980s, there has been much intensive research geared towards discovering naturally occurring HIV antibodies that can stop or neutralise the constantly mutating virus.
Professor Michael Farzan and his team at the institute have taken a new approach in building an artificial molecule. The artificial protein mimics two receptors on the surface of white blood cells to which HIV usually attaches. As a result, when the virus comes into contact with the protein, it behaves as if it is infecting a cell.
The changes that the virus undergoes in binding to the molecule effectively ‘neutralise it’, preventing it from interacting with healthy cells.
In test-tube studies, the protein neutralised 100 per centof neutralisation-resistant strains of HIV-1, HIV-2 and SHIV-AD8. In animal models, the degree of protection far exceeded that of the strongest anti-HIV antibodies produced naturally. Farzan explained the exciting results:
“We did this very stringent HIV challenge [in animals] and we kept doubling the doses. In the paper we only went four times but now we’ve given 16 times the dose to infect our control animals. And these animals were completely uninfected – zero virus. So this is better than anyone has ever shown in an animal for protection.”
However, not everyone is convinced by the research. Virologist David Baltimore from the California Institute of Technology in Pasadena is working to develop an adeno-associated virus (AAV) gene therapy that will deliver an HIV neutralising antibody. Though he finds Farzan’s work “impressive”, he remains sceptical of its applications.
“It’s perhaps a better construct than the antibodies we’ve been using, but it’s a matter of how it plays out in human trials. I don’t think it’s easy to tell how that will happen.”