For the first time, scientists say they have eliminated HIV virus from the DNA of mice, a significant step in the right direction towards a difficult cure for humans. HIV is the virus that causes AIDS, and till now, there is no cure for it.
The new study was published on the 2nd of July 2019 in the journal Nature Communications. The achievement is attributed to more than 30 scientists from Temple University and the University of Nebraska Medical Center. They made it possible by an antiviral drug in combination with the tool called CRISPR that can edit genes.
It began by engineering the mice to produce human T cells which are susceptible to HIV infection. After they infected the mice with the virus, they used a therapeutic strategy known as long-acting slow-effective release antiretroviral therapy (LASER ART) to suppress the HIV replication within the mice.
Finally, the researchers used CRISPR to remove HIV DNA from infected cells.
When the scientists later analyzed the mice, they found that HIV was eliminated in 9 out of 23 mice that were modified, so their immune systems better mimicked those of human beings.
The scientists are now keen to test their combination LASER ART/CRISPR therapy in non-human primates — and if it is successful then human trials could kick off within the year, researcher Dr. Kamel Khalili said in a press release.
Earlier, Dr. Khalili’s team at Temple had found a way to remove significant amounts of HIV DNA from rats and mice. But the method could not completely eliminate the infection. So Khalili’s lab worked in collaboration with the University of Nebraska Medical Center lab dealing with the problem differently. Together, the researchers combined the gene-editing strategy with a drug designed to beat back HIV. Howard Gendelman from UNMC told that his team’s experimental drug is engineered to act over a longer time than typical therapies. This means that it can be regulated every two or three months instead of every day. It is also better able to target HIV inside the body, he said. It is crucial that gene editing remove every last bit of the HIV virus, he said, and the drug makes that task a lot easier.
The transition from mice to humans
Dr. Steven Deeks, a professor at the University of California at San Francisco (US) who has worked broadly on HIV, acknowledged that the use of gene editing via CRISPR to remove HIV from a live animal is a significant achievement. However, he warned that using the technique on humans will be far more demanding: Scientists will have to tackle with more types of the virus, with more difficulties in delivering the gene-editing technology and the possibility of cutting up human genes while trying to target HIV, he stated. “Those are fearsome problems,” Deeks said, “especially with success depending on eradicating the virus completely.”
“For this approach to work in humans, they have to really knock out 100% of the genomes — you can not leave anything behind,” Professor Deeks said. “A single one of them can reignite the whole process.”
Though the team is very confident, yet it knows that it has a lot of ground to cover between humans and mice.
“Things that work in mice, may not work always in men,” researcher Howard Gendelman stated. “The limitations of any mice work have to do with the species, the distribution, how the drug is administered, which is a lot easier than a woman or a man.”
HIV infects more than 37 million people worldwide, according to the latest data from the WHO, and only about 22 million of those people receive antiretroviral therapy. The antiretroviral therapy only keeps the virus in check; without constant medication, the virus will quickly destroy a human’s ability to fight off disease and sickness.
Constant drug treatment can lead to other medical complications. A permanent cure to the deadly disease would bring significant benefits to millions.