An experimental vaccine against HIV has been shown to be effective in monkeys: study

New York: Scientists have discovered that an experimental HIV vaccine strategy could be effective in non-human primates. The goal of this strategy is to identify rare and vulnerable areas on HIV and teach the immune system to make antibodies to attack these areas. In this study, Rhesus macaque monkeys produced neutralizing antibodies to an HIV strain resembling the resistant viral form that most commonly infects humans, known as the Tier 2 virus.

The research provides the very first estimate of vaccine-induced neutralizing antibody levels needed to protect against HIV. "We have found that vaccine-induced neutralizing antibodies can protect animals against viruses that are very much like HIV in the real world," said Dennis Burton of the Scripps Research Institute in San Diego, California.

"Since HIV emerged, this is the first evidence that we have level 2 virus-based antibody protection after vaccination," the report said. author, Matthias Pauthner, research associate at Scripps.

Although the vaccine is far from clinical trials on humans, this study provides a proof of concept for the HIV vaccination strategy that Burton and his colleagues have been developing since the 1990s. Importantly, the study has also shown that neutralizing antibodies are the key to stop the virus.

In the study published in the journal Immunity, the team selected and re-vaccinated six low titre monkeys (antibody levels) and six high-titre monkeys. They also studied 12 non-immunized primates as a control group.

The primates were then exposed to a form of virus called SHIV, a simian version of HIV designed by engineering. This particular strain of the virus is known as the Tier 2 virus because it has proved difficult to neutralize, as have the circulating forms of HIV in the human population.

The researchers found that vaccination was effective in high-titre animals. Monkeys could produce sufficient levels of neutralizing antibodies to prevent infection.

Pauthner pointed out that it was an important discovery, because other laboratories have focused on the potential of T cells and other immune system defenses to block the infections.