Immunotherapy and HIV.

What is immunotherapy and how does it work?

Immunotherapy and vaccines

Scientists have made significant progress with a special kind of HIV vaccine. The goal: allow HIV patients to halt daily dose ARVs. ‘Immunotherapy’ is engineered to target HIV and activate specific T helper cells. This effectively kicks the virus out of hiding, then kills it. The key to this treatment is the way that immune cells are engineered to work together.

The study focused on using blood samples from HIV patients. Although yet to undergo clinical trials, thus far the results have been astonishing. If all trials succeed, HIV treatment plans will never be the same.

“A lot of scientists are trying to develop a cure for HIV,” said senior author Robbie Mailliard, Ph.D., assistant professor of infectious diseases and microbiology at Pitt Public Health. “It’s usually built around the ‘kick and kill’ concept; kick the virus out of hiding and then kill it. There are some promising therapies being developed for the kill, but the Holy Grail is figuring out which cells are harbouring HIV so we know what to kick.”

The danger of halting treatment plans

Deviating from treatment plans exposes you to higher risk than you realise. You create a lapse in the routine timing of chemical reactions designed to keep your viral load down, and you expose yourself to risks of viral relapse. The side effects can be far more serious in a relapse, without medical supervision. Worse yet: it can evolve into full-blown AIDS.

How did they do it?

Your immune system copes with a lot all at once. Part of its mission is to keep something called CMV in check. Some patients have a one in five ratio of cells specific to any one particular virus. “That got us thinking – maybe those cells that are specific to fighting CMV also make up a large part of the latent HIV reservoir. So we engineered our immunotherapy to not only target HIV but to also activate CMV-specific T helper cells.”

“You have to collect a lot of blood to find T cells latently infected with functional HIV in people on ART – it could be as few as 1 out of every 10 million cells.” In addition to the T helper cells, dendritic immune cells were also isolated for their ‘delegation’ abilities toward other immune cells. Conventional dendritic cells also have been used to induce the immune system to kill HIV. When the MDC1 was added back to T helper cells containing latent HIV, they reversed that latency as expected, kicking the virus out of hiding. And then the big test came.

“Without adding any other drug or therapy, MDC1 was then able to recruit killer T cells to eliminate the virally infected cells. With just MDC1, we achieved both kick and kill – it’s like the Swiss Army knife of immunotherapies. To our knowledge, this is the first study to programme dendritic cells to incorporate CMV to get the kick, and also to get the kill.”

The team is now pursuing funding to begin clinical trials to test this property of MDC1 in humans.

Sources:

Houser, K. 2019. First of its kind HIV therapy draws out the virus, then kills it. Futurism. 5 April. Available at: https://futurism.com/the-byte/hiv-immunotherapy-draws-cells-kills-them [Accessed 30 July 2019].

University of Pittsburgh Graduate School of Public Health. 2019. Immunotherapy Kicks, Kills HIV by Exploiting a Common Virus. [Press Release]. 3 April. Available online at: https://www.upmc.com/media/news/040319-kristoff-mailliard-mdc1 [Accessed 30 July 2019].

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