In the case of Covid vaccines, the instructions were for a piece of the coronavirus.
In the new study, they are for molecules key to targeting HIV.
Dr Sharon Lewin, director of the Doherty Institute at the University of Melbourne, who led the study, called mRNA a “miraculous” tool “to deliver things that you want into places that were not possible before”.
Vaccines deploying mRNA instruct the body to produce a fragment of the virus, which then sets off the body’s immune response.
In the United States, the shots were initially hailed for turning back the pandemic, then viewed by some with suspicion and fear.
Some American officials, including Health Secretary Robert F. Kennedy jnr, have falsely said that they are highly dangerous and even deadly.
The researchers plan to test the method in HIV-infected animals before moving to clinical trials. Photo / Joe Raedle, Getty Images
The US Department of Health and Human Services has sought to limit the vaccine’s availability to pregnant women, children and healthy younger adults.
A week ago the Trump Administration cancelled a nearly US$600 million ($997m) contract with the drugmaker Moderna to develop an mRNA shot for humans against bird flu.
“The fear right now is not rational,” Lewin said, adding that “mRNA vaccines have been given to millions of people around the world, so we have a very good understanding of their risks”.
The new study describes the use of mRNA as a tool to flush HIV out of its hiding places.
Other uses could involve providing proteins missing from those with certain diseases or correcting genetic errors.
Frauke Muecksch, a virologist at Heidelberg University in Germany who was not involved in the work, called mRNA a “promising, absolutely powerful technology”.
Although most people may have only heard of mRNA’s use in science during the pandemic, scientists have been working with it for more than 20 years, she said.
“I think it’s not just therapeutically very powerful, but also for basic science, for research, it opens up a lot of avenues,” she added.
Potent antiretroviral drugs can now control HIV, suppressing it to undetectable levels.
Still, minute amounts of the virus lie dormant in so-called reservoirs, waiting for an opportunity to resurge.
A cure for HIV would involve ferreting out all of this virus and destroying it, a strategy that has been called “shock and kill”.
HIV cure potential: mRNA study reveals breakthrough in virus activation. Photo / Getty Images
A significant hurdle is that the virus lies dormant in a particular type of immune cell, called a resting CD4 cell. Because these cells are inactive, they tend to be unresponsive to drugs.
The few drugs scientists have previously used to rouse the virus in these cells were not specific to HIV and had unwanted side effects.
“It’s fair to say the field’s been a little bit stuck,” said Brad Jones, a viral immunologist at Weill Cornell Medicine who was not involved in the latest research.
In 2022, Jones and his colleagues found that the immune boost from the mRNA vaccines awakened latent HIV in people living with the virus. (Other research has shown that mRNA vaccines also activated dormant viruses including Epstein Barr.)
“You get just a little bit of a gentle nudge with some of these vaccines, and it’s enough to coax some of these latent viruses out so they can be killed,” Jones said.
Lewin and her colleagues had for years experimented with other ways to activate HIV but had no luck in resting cells.
Seeing the success of the Covid vaccines, which used lipid nanoparticles – tiny spheres of fat – containing mRNA, her team tested similar particles.
They used the particles to deliver two different sets of molecules: Tat, which is adept at switching HIV on, and CRISPR, a tool that can “edit” genes.
The researchers showed that in resting immune cells from people living with HIV, the approach coaxed the virus out of dormancy.
The method will be tested in HIV-infected animals before clinical trials. Photo / Getty Images
“It’s very, very hard to deal with these cells, so I think this really targeting the right population of cells is what makes this paper special,” Muecksch said.
It’s unclear whether the new approach can successfully awaken all of the dormant HIV in the body, and what side effects it might produce.
Lewin said that “mRNA will almost certainly have some adverse effects, as every drug does, but we will investigate that systematically, as we do for any new drug”.
In this case, she said, side effects may be more acceptable to people living with HIV than having to take medications for the rest of their lives.
The researchers plan to test the method in HIV-infected animals next, before moving into clinical trials.
