Body + Brain

12
Sep

Vaccine Eliminates HIV-Like Virus in Monkeys

For decades now, HIV has been a seemingly unstoppable epidemic. While the virus’s spread has stabilized in the U.S. and even dropped in hard-hit Subsaharan Africa, there are still about 33 million people living with HIV worldwide.

This summer, there was renewed hope for a cure when two patients treated at Brigham and Women’s Hospital in Boston had all detectable traces of the virus removed from their bodies. It was a grueling treatment, though, involving bone marrow transplants followed with chemotherapy, a procedure that has a 20% risk of death. But it was the first time patients without a beneficial mutation in their marrow donor cells were rid of HIV, which gave doctors hope.

Despite that progress, we’re still far from a cure. Here’s Teal Burrell, reporting for NOVA Next:

“It’s a proof of concept,” says Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. “It says that even though you, in fact, have a very unusual situation, you can at least prove that it’s possible to rid the body of HIV.”

“This is not a practical approach for the thousands and millions who are HIV infected who would like very much to be off antiviral therapy,” he adds. “Obviously we are going to have to figure out a way to [get rid of the virus] that isn’t such a high-risk endeavor for the patient.”

Fortunately, researchers have just announced another breakthrough. It’s still not a cure, and it only works in monkeys, but it provides a glimpse at what an HIV vaccine might look like.

siv-particles
Budding, immature, and mature SIV virus particles

Researchers tested the new vaccine on monkeys infected with a particularly deadly strain of simian immunodeficiency virus, or SIV, a close relative of HIV. The strain is up to 100 times more deadly than HIV and typically kills infected monkeys within two years. Rebecca Morelle describes how the vaccine works for BBC News:

The vaccine is based on another virus called cytomegalovirus (CMV), which belongs to the herpes family.

It used the infectious power of CMV to sweep throughout the body. But instead of causing disease, it has been modified to spur the immune system into action to fight off the SIV molecules.

rhesus monkey
The vaccine cleared SIV from infected rhesus monkeys.

“It maintains an armed force, that patrols all the tissues of the body, all the time, indefinitely,” explained Prof Picker.

The researchers gave rhesus macaque monkeys the vaccine, and then exposed them to SIV.

They found that at first the infection began to establish and spread. But then the monkeys’ bodies started to respond, searching out and destroying all signs of the virus.

The vaccine worked in half of the monkeys that were infected, which, given how deadly the strain is, could be the best it can do, the researchers say. Next, they are going to see if their concoction can clear SIV from monkeys that already have the infection. They’re also working to create a version that’s safe for human trials, which could happen just two years from now.