In a bid to someday provide people with the ability to fend off HIV, the Bill & Melinda Gates Foundation awarded $5.8 million on Thursday to vaccine researchers.
A novel genetic engineering approach garnered the award for a Scripps Research Institute group in Jupiter, Florida, who hope to create the first effective HIV vaccine. HIV, the virus that causes AIDS, infects about 2 million people worldwide every year.
The key to the new approach is that technically, it isn't really a vaccine.
Rather than teach the immune system to fight HIV like a standard inoculation, the new method delivers genes into muscle cells and effectively re-engineers our bodies to fight off the virus.
In February, the group showed that these genes successfully eliminate the virus from monkeys and protect them from future infections.
"It's taking what is a basic gene therapy technology and using it to address the problem of a HIV vaccine," Michael Farzan, the professor of immunology and microbiology at Scripps who was awarded the grant, told BuzzFeed News. "We've got to think about getting away from the conventional mode of thinking about vaccines, especially when it comes to HIV."
Despite the recent promise of gene therapy, some scientists worry that a fully effective human vaccine is still many years away.
"There's no guarantee that we'll get an HIV vaccine — the jury's still out," Carl Dieffenbach, director of the division of AIDS at the National Institute of Allergy and Infectious Diseases, told BuzzFeed News.
Traditional vaccines introduce weak or dead pathogens into our bodies, training the immune system to attack the disease.
Once our immune cells learn which specific antibodies are needed to defeat a specific virus, we can be protected for long periods of time.
HIV, however, is a cunning virus. It's both incredibly diverse and mutates rapidly within our bodies. The virus also infects the very immune system that's meant to fight against it. To successfully beat the virus, our bodies need to be able to produce antibodies that can fight many strains of a constantly mutating target.
That helps explain why scientists have struggled to make an HIV vaccine for nearly 30 years. AIDS has claimed nearly 39 million lives to date, despite the discovery of treatments for infected patients in the 1990s.
In 2009, a group led by Philip Johnson at the Children's Hospital of Philadelphia discovered that gene therapy might bypass the immune system altogether to craft new kinds of HIV vaccines. Johnson figured out how to package antibody genes inside a virus, which then specifically invades muscle cells. Once inside the cells, the viruses park there, turning the muscle cells into factories to produce the desired antibodies.
Johnson's technique worked. While monkeys who had the powerful gene delivered were protected from doses of the primate version of HIV, the monkeys without it died.
A huge boost to HIV vaccine hopes came a year later, when scientists discovered antibodies more powerful than any others previously found in people. They resided in the cells of a 60-year-old black gay man known only as Donor 45. Unlike most antibodies, these so-called broadly neutralizing antibodies (BNABs) fought back against HIV, wiping out nearly 91% of its strains.
BNABs have since become the "holy grail" of HIV vaccine research, Richard Jefferys, director of basic science, vaccines, and cure projects at the Treatment Action Group, told BuzzFeed News.
Many researchers have been trying to figure out how to coax our immune systems to produce BNABs on their own using traditional vaccines. But Farzan, as well as Johnson, wants to get around the immune system entirely.
Farzan and his colleagues have taken Johnson’s research one step further, engineering a gene that would code for an artificial antibody more powerful than anything that’s ever been seen in humans.
Antibodies do their work by recognizing and latching on to signature molecules coating invading cells. While most BNABs grab on to one key molecular site conserved across all HIV strains in order to disable them, Farzan's artificial antibody grabs on to an additional one essential to the virus's attack.
With the $5.8 million from the Gates Foundation, Farzan will first test the artificial antibody in cells and then in animals to make sure that it's safe. Eventually, the antibody — wrapped in its viral packaging — can be tested as a vaccine in individuals at high risk of contracting HIV to see how well it protects them from infection.
But even if it is successful, Farzan and others caution that a genetically engineered HIV vaccine is still many years and many many millions of dollars away.
"It seems to be extremely powerful — that's why so much of the scientific community has gotten excited," Thomas Hassell, vice president of vaccine development for the International AIDS Vaccine Initiative, told BuzzFeed News.
"But will it prove to be powerful enough in the face of HIV, which is so extraordinary in its diversity, so cunning in its escape mechanisms? You need a truly extraordinary response to be able to deal with that extraordinary of an invader."