HIV Vaccines: New Insight for Researchers

(Ivanhoe Newswire) –While most people are rushing to get their flu vaccine this time of year, scientists have new insights in their efforts to develop a HIV vaccine.

Researchers at Duke University Medical Center have announced that by analyzing the structure of antibody-virus complexes produced in vaccine recipients, they have revealed how the vaccine triggers immune responses that could fight HIV-1 infection.

Approximately 34 million people in the world are infected with HIV. The development of a safe and effective vaccine has been a priority for quite some time now. In 2009, a vaccine efficacy trial showed that the RV144 HIV-1 vaccine protected close to one third of study participants from getting infected. A more recent study at Duke found that vaccine-induced antibodies targeting variable regions 1 and 2 (V1-V2) of the virus are associated with a lowered risk of HIV-1 infection. However, until now it has been unclear whether these antibodies are crucial for protection against the virus or how they might fight off infection.

"This is the first comprehensive study of the repertoire of antibodies that were induced by an HIV vaccine and were associated with decreased transmission of HIV. Ultimately, the motivation of the study is to understand how that vaccine works in order to develop ways to make it better,” senior study author, Barton Haynes, at Duke University Medical Center, was quoted as saying.

Researchers isolated antibodies from RV144 vaccine recipients and determined the antibodies’ crystal structures alone and with HIV-1. They discovered that the V2 region, which is targeted by antibodies that includes amino acid residue 169, exhibits extreme variation in structural conformation and amino acid sequence. Despite this variation in HIV-1, the antibodies can still recognize position 169 on the virus and binds it to virus-infected immune cells and targets them for destruction.

"New technology is allowing the dissection of a complex set of vaccine-induced responses such that new vaccines can be designed to hopefully improve on the beachhead that the RV144 trial provided to the HIV-1 vaccine field," Haynes concluded.

SOURCE: Immunity, January 2013