In addition to marking the official start of the count-down to Christmas, December 1st is also World AIDS Day. As excited at we are here at CERG about our lovely Advent calendar,* this aspect of the day also deserves recognition.
Rightly, there is an abundance of news about HIV/AIDS today, particularly discussing the perception of the disease in the public mind (e.g. NYT). This is not uncommon – HIV/AIDS is still a very misunderstood disease in many parts of the world, and education to reduce the social stigma and prevent further infection remains important.
But what about the scientists?
In spite of all the faith we have in modern medicine and the advances of science, the human immunodeficiency virus is still giving scientists a remarkable amount of trouble. The Nature News blog reported earlier this week that two arms of an important HIV prevention trial called VOICE had been cancelled. These had tested the use of a vaginal gel with an anti-retroviral drug, tenofovir, as well as taking the same drug orally. Despite impressive preliminary trials, including a very promising study published in Science last year, further trials had failed to show an effect. As it stands now, the remaining two arms of VOICE are still in progress, delaying the complete publication of trial data and public analysis of why the drugs proved unsuccessful.
Dreaming of a good vaccine
The all-protective HIV vaccine remains an elusive goal. In broad terms, vaccines elicit a protective immune response that generates specific antibodies. The antibodies then circulate in the bloodstream and protect against infection by attaching to epitopes on the virus, making it a glaringly obvious target for the immune system to eliminate. Scientists have actually discovered several antibodies that are capable of neutralizing most HIV strains. The problem lies in eliciting an immune response that actually targets the same epitopes as the neutralizing antibodies do, and so far no vaccine has managed to do this successfully.
By contrast, an interesting paper published in Nature yesterday takes a different approach to antibody protection. Recognizing the problems with a vaccine, Balazs and colleagues used a vector-mediated gene transfer to genetically engineer secretion of these known neutralizing antibodies into the circulation, thus providing protection. (The experiment was done in mice.) Essentially, they genetically modified an adeno-associated virus – a small virus not known to cause disease – optimizing it for producing complete antibodies in muscle cells. After some tweaks, they found that a single intramuscular injection of the virus induced lifelong expression of the neutralizing antibodies in the mice, and the mice seemed fully protected from HIV infection. Wow.
If this approach can be translated to humans with equal success, there is real hope of an effective prophylactic against HIV. It might not be in the form of the much longed-for HIV-vaccine, and for now the picture is still far from rosy. But these findings represent a real ray of hope in an otherwise gloomy situation.
*(all Norwegian posts – our apologies to the English-only readers!)
Written by Hanna Sofie Ellingsen at CERG.