In exiting new research published in Nature Communications, a team from the Salk’s Gene Expression Laboratory have managed to customise a defence system used by many bacteria (CRISPR) and trained this scissor like machinery to recognize the HIV virus. This could be the first step in creating a drug that could not only prevent HIV infection, but also treat patients already infected with the HIV virus and possibly even remove dormant copies of the virus. This could potentially revolutionise the fight against HIV.
When HIV infects a cell it hijacks the cells machinery to make further copies of itself and it buries these copies in the cells own genes. This is why it has so far been impossible to cure HIV, as whilst current drugs can suppress the virus to undetectable levels in the blood of infected patients, the dormant HIV can always reactivate and make more copies of itself, basically topping up the infection. The current drugs we have target various different stages of the HIV virus life cycle but they cannot remove the copies of HIV already buried in the DNA.
The team therefore looked at ways that bacteria protect themselves from viral infection. One of the mechanisms is a molecular defence system called CRISPR that bacteria use to cut up viruses. They wanted to see if we could hijack this system to also cut up HIV, even the copies of HIV already inserted into the DNA. When they tested the mechanism, they found that it worked and it removed 72% of infected cells. They also noted that CRISPR didn’t only chop up the loose copies if HIV but also the dormant HIV. This could potentially pave the way for creating a drug that can prevent HIV infection altogether and also more importantly potentially get rid of the so called latent reservoir, the main barrier to an HIV cure.
There are some questions that still need answering such as how well the mechanism will work in humans and whether HIV, which evolves quickly, will evolve to escape CRISP, but nevertheless it is a promising discovery.