The problem in trying to cure HIV is the so called latent reservoir. These are bits of HIV that remains hidden in reservoirs in the body, even when the virus is being fully suppressed in the blood. This is the reason that if someone discontinues their ART the virus rebounds. It is also why all attempts at curing HIV so far have failed. Scientists have been trying to lure dormant HIV into the open in the hope that this would facilitate a cure, but so far most efforts have been thwarted. A new study published in the Journal Nature gives us some clues as to why this is and maybe some ideas of how to better go about this in the future
One of the problems with HIV eradication therapy is that HIV has an uncanny ability to mutate so that it becomes unidentifiable and resistant to destruction from the bodies immune system, even when we manage to coax it out of hiding.
However the researchers found a way of training the immune system to recognize and attack HIV once it has been coaxed out. What they did was they trained a class of immune sentinel cells known as killer T cells to spot and destroy these elusive HIV infected cells. This is an excellent new strategy which will hopefully be more successful than past efforts. It was always thought that all we needed to do was coax the dormant HIV infected cells out of hiding and we could finish them off, but it seems that not only do these dormant cells hide, they also mutate so they become unrecognisable by the immune system, even after latency reversal.
Dr Robert Siliciano, professor of medicine, molecular biology and genetics at Johns Hopkins University said that ” luring HIV out of its hiding place is winning only half the battle”
All viruses carry markers that are spotted by our immune systems as foreign, which then sets of an attack. However in the case of HIV the virus alters these markers soon after infection. However Dr Siciliano and colleagues reported that there is always a bit of the HIV virus that remains the same and thought this could be exploited so that they could train the killer T cells to spot these unaltered areas. And that is exactly what they did.
The killer T- cells trained to recognise the HIV managed to destroy 61% of the infected cells , where as the cells that were not primed, killed only 23% .They then tested the approach on mice and it worked !
They concluded that any curative strategy would need to include use of these primed killer t cells. This study is an important step forward in the search for a cure. Watch this space!