Miranda Smith
HIV evades gene editing attempts
A new study shows that using gene scissors to remove HIV from an infected cell may not be as effective as hoped.
Several years ago, it was shown that specialised gene scissors could remove specific genes, such as CCR5, that would stop HIV in its tracks by making cells resistant to infection. These gene scissors (called Zinc Finger Nucleases) are now in clinical trials. The next development was to target the gene scissors to HIV itself and effectively turn an HIV positive cell to an HIV negative cell. This is an exciting concept but still at the test tube stage.
Gene editing for HIV seems like a pretty nice way to eliminate latent virus that can hide in resting cells while a person is on antiviral therapy. We wrote only a couple of weeks ago about a study showing the successful removal of latent HIV. But new research is telling us that this might be more complicated than first thought. Using laboratory models of latent HIV infection, researchers from Canada showed they could remove HIV using new gene scissors – called CRISPR/Cas9. But when they followed these gene modified infected cells over a long period of time, they found that HIV rapidly developed resistance to the gene scissors. Resistance occurred even when there was just a single change in the genetic code of the virus.
HIV was able to change the spot where the molecular scissors usually slice the virus out – when this site was changed, the scissors no longer knew where to cut and the virus continued on its merry way.
Professor Lewin, Director of the Doherty Institute and an infectious diseases physician and HIV cure researcher said “Using gene scissors to eliminate HIV is an interesting new approach, still in the early days of development. There will be lots of challenges getting this to the clinic, the main one being the gene scissors finding an infected cell, as these cells are so rare. This research also tells us that resistance might be a problem too.”
The researchers hope that by using different ‘scissors’ for different parts of the virus, gene editing still has a role in developing a way to eliminate and control HIV.
Read more at Cell Reports
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