BY Neal Broverman
December 09 2009 7:35 PM ET
Researchers at the University of California, Los Angeles, made an astounding announcement Monday — stem cells could be engineered to target and kill HIV. In an interview with Advocate.com, Scott Kitchen, assistant professor of medicine at UCLA's David Geffen School of Medicine, talks about the technology that made this discovery possible and how close these findings lead us to a vaccine.
How do the stem cells work against HIV?
As you know, HIV is a lifelong infection. The immune system of a human is capable of responding to the virus and having an effect on its ability to replicate within the body, but ultimately it fails to clear the virus from the body, versus influenza or cold viruses. So what we were looking to do was find ways to restore the immune response in HIV-affected people in a way that specifically targets HIV itself. So we took cells from the blood of HIV-infected people — people who have an ongoing infection but [not enough T] cells to completely eliminate the virus from the body. We took the cells that were there, identified a specific cell and a specific molecule on that cell that targets the cell toward HIV. So we molecularly cloned that molecule and took stem cells from another tissue source, another donor. This tissue is basically blood stem cells, and we engineered those blood stem cells ... to target HIV infection.
In order to test this in a living system, the genetically modified stem cells were placed into tissue that had been implanted into a mouse. This allows us to study the effects of the development of the stem cell into a mature T cell that is targeted to HIV in a living, breathing organism. In this model, we established this procedure allows the development of HIV-specific cells. So, the next step is to expand this into a system that allows us to examine the effects of these cells on HIV replication in vivo — basically another animal-based system that allows us to look at the effects of these types of cells, these targeted HIV-specific cells, in eliminating the virus or lowering viral infection.
Was it previously believed that stem cells could destroy HIV, but it just wasn’t proven?
There have been studies performed with mice cells that showed you can [alter and clone mice cells so they could battle] various mouse viruses. It was unknown whether you could perform this with the human system. The big advancement here is that you can. You can genetically engineer human blood stem cells to develop into T cells that specifically target HIV.
When did this study begin?
About three years ago as a concept. It really took off about a year ago as the technology became more and more conducive to allow the molecular cloning of these molecules.
So the technology made this advancement possible?
The technology to clone these T-cell receptors had been really a challenge prior to the current study. We’ve managed to more efficiently identify these molecules.