Scientists eliminate HIV from cultured human cells for first time

U.S. scientists said Monday they have designed a way to precisely remove the AIDS virus from cultured human cells without damaging them for the first time, a discovery they said could lead to a potential cure for the disease.

Researchers from Temple University School of Medicine successfully eliminated latent HIV from human cells by using a combination of a DNA-snipping enzyme called nuclease and a targeting strand of RNA called guide RNA (gRNA) to hunt down and excise the HIV DNA.

From there, the cells were able to repair themselves and solder the loose ends of the genome back together, resulting in virus- free cells.

"It's an exciting discovery, but it's not yet ready to go into the clinic," Kamel Khalili, professor and chair of the Department of Neuroscience at Temple," said in a statement. "It's a proof of concept that we're moving in the right direction."

The findings, led by Khalili and his colleague, Wenhui Hu, associate professor of neuroscience at Temple, were published in the U.S. journal Proceedings of the National Academy of Sciences.

Although antiretroviral therapy has significantly cut the death date in people with HIV, it can't entirely clear the virus out of their bodies, Hu explained to Xinhua.

"In order to cure the disease, eradication of HIV-1 entire genome from host cells is required," he said.

In the new study, the researchers engineered a 20-nucleotide strand of gRNA to target the HIV DNA and paired it with the Cas9 nuclease.

The gRNA targets the control region of the gene called the long terminal repeat (LTR), which are present on both ends of the HIV-1 genome, the researchers said.

By targeting both LTRs, the Cas9 nuclease can snip out the 9, 709-nucleotides that comprise the HIV genome.

The combination approach was successful in several cell types that can harbor HIV-1, including microglia and macrophages, as well as in T-lymphocytes, Hu said.

The same technique could theoretically be used against a variety of other viruses, he said.

They also suggested that the molecular tools also hold promise as a therapeutic vaccine.

Still, the technique faces several significant challenges before it is ready for patients, they acknowledged.

The challenges included how to deliver the therapeutic agent to every single infected cell and how to individualize it to meet every patient's unique viral sequences since HIV is prone to mutations.

"We are working on a number of strategies so we can take the construct into preclinical studies," Khalili said. "We want to eradicate every single copy of HIV-1 from the patient. That will cure AIDS. I think this technology is the way we can do it."