Collaborative Study To Find Therapies To Reduce HIV Reservoir Development

Researchers at the University of Cape Town are involved in a collaborative study with other researchers throughout the world may have unexpectedly found new therapies that would help decrease the HIV reservoir – a huge barrier to come up with an HIV cure.

This reservoir is made up of viral DNA that hides within the body even after using antiretrovirals. The antiretroviral treatment will suppress HIV but is unable to cure it. They can stop the speed in which HIV develops into AIDS, decreasing the viral load so that it’s nearly undetectable, if not just undetectable.

This therapy is unable to destroy the virus completely because it can be found in the reservoirs in the immune cells’ DNA. HIV imprints itself into the CD4’s immune cells, waiting for a time that it can replicate itself should a person stop taking the antiretrovirals.

How this reservoir develops has been, for the most part, elusive. Scientists have theorized that it constantly forms during the infection before treatment begins. However, it appears that this isn’t the case and that the start of the antiretroviral treatment is changing the human immune system that allows an HIV reservoir to develop.

Carolyn Williams, head of the Division of Medical Virology at UCT, said scientists hope to decrease the reservoir size that will lead them to stop antiretroviral treatment and not let the virus attack again.

Since it can be persistent for decades, people must remain on the treatment for the rest of their lives. The reservoir is what is keeping scientists from actually developing a cure for HIV, and not knowing how it develops is what hinders them from eliminating it.

Nine women in South Africa had blood samples taken for a study to understand when the HIV reservoir begins.

HIV is a virus that quickly evolves, making billions of copies every day, and with a sloppy genetic copy, there are all kinds of mutations. This is the way in which researchers are mapping out the evolution of the virus.

Looking at the virus’ genetic sequence of the women’s hidden reservoir with the active virus’ sequence, researchers could get an idea of when the reservoir is created.

• If the reservoir’s viral sequences are similar to that of the bloodstream virus around the time treatment began, it’s an indication that this is when the reservoir developed.
• If the reservoir sequences are similar to the virus at the start of the infection, but before treatment, it would indicate that it’s developed throughout the infection.

According to UCT Division of Medical Virology Dr. Melissa-Rose Abrahams, most of the reservoir viruses were similar to the viruses that have been in action within the year treatment began. This is higher than a continuous reservoir before the onset of treatment. It’s suggestive that the immune cells infected with the virus when treatment starts goes silent and hides into the reservoir.

There have only been two cases where HIV has been cured – one in London, another in Berlin. This was only possible because of the rare circumstances that cannot be reproduced in the 38 million HIV individuals.

Abrahams said there is a chance for an intervention. She said if a biological intervention could be found, it could help decrease the amount of infected cells there were at the time treatment begins and restrict the viral reservoir.

Researchers are currently looking at the idea that starting antiretrovirals is hindering the body’s immune system by decreasing active HIV, which then lets the immune cells where HIV is at to become long-lived memory cells and may even become a long-term viral reservoir.