Researchers Get Closer to Global HIV Vaccine

Researchers looking for a global vaccine for HIV are reporting progress in clinical tests with monkeys, showing that bioinformatically optimized HIV vaccine antigens known as "mosaic" antigens might be useful in the design of a global HIV vaccine.

The research, which was led by a team at Beth Israel Deaconess Medical Center (BIDMC), was published Thursday in the journal Cell.

"A global HIV vaccine would offer major biomedical and practical advantages over most other HIV vaccine candidates, which are limited to certain regions of the world," said lead author Dr. Dan Barouch. "To our knowledge, this study represents the first evaluation of the protective efficacy of a candidate global HIV antigen strategy in nonhuman primates."

In their tests, the researchers found that rhesus monkeys can be protected against a stringent simian-human immunodeficiency virus when given mosaic HIV vaccine antigens.

Although many of the monkeys ultimately did become infected with HIV, the researchers found that monkeys immunized with the mosaic HIV vaccine showed an 87 percent to 90 percent reduction in the probability of becoming infected each time they were exposed to the virus.

A control group given "sham vaccines" became infected more quickly, the researchers said.

"These findings indicate that these optimized vaccine antigens can afford partial protection in a stringent animal model," Barouch said, adding that the immunized monkeys were able to mount an immune system response to diverse strains of HIV.

"Protection was dependent on several different types of antibody responses, suggesting that the coordinated activity of multiple antibody functions may contribute to protection against difficult-to-neutralize viruses," he said, noting the monkeys also mounted cellular immune responses to multiple regions of the virus.

Barouch also hinted of promise, as the types of immunoviruses the monkeys were tested on were about 100 times more infectious then the typical sexual HIV exposures in humans.

"These data suggest a path forward for the development of a global HIV vaccine and give us hope that such a vaccine might indeed be possible," said Barouch. "We are planning to advance this HIV vaccine candidate into clinical trials next year," he adds.