NEW YORK (CNN) — Researchers have successfully eliminated HIV from the DNA of infected mice, a promising step toward a cure for the nearly 37 million people living with the virus.
In a study published Tuesday in Nature Communications, researchers from Temple University's Lewis Katz School of Medicine and the University of Nebraska Medical Center (UNMC) coupled genome editing technology with a slow-release virus suppression drug to eliminate HIV cells entirely from some infected mice.
Current HIV treatment cannot eliminate the virus entirely but does suppress its replication. Antiretroviral therapy, or ART, requires lifelong use to stall the virus' spread and, as a May study found, can potentially end the transmission of HIV between sexual partners.
Testing their methods on a group of infected "humanized mice," or rodents engineered to produce human T cells susceptible to HIV, researchers administered a treatment called LASER ART, or long-acting, slow-effective release ART, to suppress HIV cells from replicating.
The team modified the drug for a slow release across several weeks, targeting tissue in the spleen, bone marrow and brain where latent HIV reservoirs, or clusters of inactive HIV cells, were likely to occur.
To eliminate the remaining infective cells from the subject's DNA, they employed a gene editing tool called CRISPR-Cas9.
The process allowed the teams to "clean segments of the genome" and remove the HIV chromosome, co-author Kamel Khalili told CNN.
By the study's end, researchers had successfully eliminated the virus from nine out of 23 mice.
The results prove that HIV can be eliminated, researchers say
The two labs initially began their research separately: Howard Gendelman at UNMC pursued trials with LASER ART, while Khalili at Temple University had been tampering with CRISPR technology for five years.
They combined their efforts to attempt complete elimination of the virus. And their lofty goal required a unique approach.
Khalili said he treated HIV as a genetic disease: Once the virus infects a subject, the viral genome enters into the chromosome and becomes a "bad gene," he said.
Combination therapy was a prime way to attack HIV from both angles: Slow its spread first with LASER ART, then edit it out completely with CRISPR.
To confirm they'd eradicated the virus, a process that took years, Gendelman told CNN the team examined every "nook and cranny" of the mice's tissue where infected cells may lurk.
The results are proof that elimination of HIV is possible—but they're just a first step, not a leap straight to cure, he cautioned.
"We're landing on the moon," he said. "It doesn't mean you made it to Mars yet."
Khalili's labs have been working on a version of the study with primates, though it'll take between 9 months to one year to discern if the virus is eradicated. A paper based on the short-term results of gene editing in primates could be published within the year, he said.
If their methods continue to prove successful, clinical trials could follow as soon as next summer, he said.
Recent attempts to cure HIV have sparked hope
Hope for a cure swelled in March when researchers announced a second person had been effectively rid of HIV after a stem cell transplant successfully eliminated any trace of the virus from his blood.
Both patients, known as the London and Berlin patients, were treated with stem cell transplants from donors born with the CCR5 genetic mutation that made them resistant to the virus. The men, already infected with HIV, were diagnosed with forms of cancer when they received the treatment.
The London patient had been in sustained remission for 18 months at the time the article was published, researchers said.
In 2018, an HIV vaccine concept got the go-ahead for further testing after a study found it induced an immune response in humans and monkeys. Its effectiveness in protecting humans from the virus is still unknown.
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