HIV: from pathogen to ally

The HIV virus is one of the world’s most deadly killers. We are now 30 years into a global pandemic and the estimated number of deaths from AIDS worldwide is around 24 million, with a further 33 million currently living with HIV.

But that’s not the whole story. To commemorate World AIDS Day, Professor Mary Collins’ Lunch Hour Lecture presented a radical idea: using the HIV virus as a new medicine.

Although the thought of injecting HIV doesn’t immediately sound like an appealing prospect, there are quite a few convincing arguments as to why it’s a good idea, and of course, virologists go in for a bit of genetic jiggery-pokery before coming at you with a needle.

Their thinking goes a bit like this. One of the reasons that HIV is such a devastating disease is that the virus is very effective at targeting blood cells and hijacking their genetic material by inserting viral DNA into the hosts’ DNA. But what if you could engineer HIV so it contained DNA that coded for the proteins that are missing in patients with genetic diseases like beta thalassemia and Parkinson’s? Scientists would then be able to use the virus’s own vicious efficiency at infecting cells as a method of delivering gene therapy. Brilliant.

Professor Collins outlined one particular case study where scientists in Paris have had particular success using this method. The debilitating disease Adrenoleukodystrophy (made famous by the film Lorenzo’s Oil) is characterised by fatty acid accumulation in the brain which leads to inflammation and gradual loss of motor, and then cognitive, function. Most people with the disease die in their early teens.

The team in France were able to genetically engineer HIV DNA so that it contained a functional gene to replace the faulty one in Adrenoleuodystrophy patients. They injected their altered virus into patients’ bone marrow with astounding results – patients showed significant halting of their symptoms, with only very minor loss of motor function and no progressive loss of cognitive function.

However, there are limitations to this form of gene therapy. It only works for single gene disorders and you need to be able to target enough of the virus to the affected tissue, so this method isn’t going to work for patients with diseases like cystic fibrosis.

Professor Collins then moved on the work that she is doing in her lab on using HIV as the basis for vaccines. As HIV is an auto-immune disease it is very good at targeting blood cells which fight pathogens, specifically by locating ‘antigen presenting cells’ which trigger our immune system.

A particular focus of this work is developing vaccines for influenza, and preliminary vaccines have been developed and tested in mice.

This lecture introduced the audience to several difficult, although profound, ideas about immunology and gene therapy. At times it was slightly difficult for the layperson to follow all the diagrams, although I suspect there were many immunologists in the room as Professor Collins was overrun with questions at the end. As is usually the case with the Lunch Hour Lectures series, the question section brought up some interesting points, including why scientists haven’t spent more time using these methods to target HIV infection itself, and the possible risks of triggering cancers by meddling with DNA in this way.

For more information on the topic I’d recommend this article in the Observer which includes an interview with Professor Collins. This is definitely a topic that deserves further investigation – and it’s certainly the most positive lecture about HIV I’ve ever been to.

Clare Ryan is Media Relation Manager in UCL Communications & Marketing.

Watch the full lecture here: