The team used three different types of mice for their most recent experiments. First type is infected with latent HIV lurking in its cells, the same type they used for their trials in 2016, while the second one has actively replicating HIV in its system. The last type is grafted with human immune cells, including T cells that have latent HIV in them. HIV can actually hide in the immune cells that are supposed to kill them, which is one of the reasons why it's hard to find a cure for the condition. While anti-retroviral therapies allow HIV patients to live a normal life, they're far from perfect. As Khalili explained:
"The current anti-retroviral therapy for HIV is very successful in suppressing replication of the virus. But that does not eliminate the copies of the virus that have been integrated into the gene, so any time the patient doesn't take their medication the virus can rebound."
To introduce their CRISPR system into mice without being attacked by its immune system, the researchers attached it to adeno-associated virus that doesn't typically trigger a response in the body like other viruses do. The system eliminated the rodents' HIV as the AA virus replicated. While successful, the team still has to make sure their system only snipped away the HIV and none of the good DNA. That's why they're planning to repeat the experiments on primates, whose DNA is closer to humans. Ultimately, they hope to follow in the footsteps of the Chinese oncologists from Sichuan University who already conducted CRISPR human trials.