Main | Wednesday, February 04, 2009

HIV Gene Therapy Trial Begins

A minute percentage of the population is naturally immune to HIV due to a mutated gene called CCR5. Just launching is a trial which seeks to immunize against and cure HIV by clipping CCR5 out of the t-cells of infected patients.
Since the discovery that a small portion of people who are exposed to HIV do not get infected, scientists have been working to discover the secret to those people's resistance and how to make others resistant as well. It turns out that most people have a gene called CCR5, which makes them vulnerable to HIV infections. The naturally resistant people have mutant CCR5 genes that inhibit HIV.

Previously, scientists found that by cutting the CCR5 gene out of white blood cells involved in the immune response known as T-cells, they could protect a tube full of human cells from the virus. The gene editing technique relies on proteins called zinc finger nucleases that can delete any gene from a living cell. In theory, zinc finger nucleases could give that immunity to anyone.

The procedure is simple: Take some healthy T-cells out of an HIV patient, clip out their CCR5 genes, grow more of these clipped T-cells in a dish, and then put them back in the patient. "In this first study we will re-infuse approximately 10 billion of these cells back into the participants, and we will see if it is safe and if those cells inhibit HIV replication in vivo," said Tebas. "We know they do in the test tube."
If this works, the technique could both cure HIV in infected patients and provide immunity to the uninfected. The study is being launched only in patients who are resistant to existing HIV medications. It should be noted that even if this technique is completely successful, such a process is out of the reach of the vast majority of people in the world.

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