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Issue No. 7 | February 16, 2007

News and Features

NIAID and South African AIDS Vaccine Initiative Moves Forward with Large-Scale HIV Vaccine Trial

A large-scale HIV vaccine trial has opened in South Africa. The study, also known as HVTN 503, plans to enroll up to 3,000 HIV-negative men and women. This promises to be the largest HIV vaccine trial in Africa to date.

This trial is being jointly conducted by the National Institute of Allergy and Infectious Diseases (NIAID), the HIV Vaccine Trials Network (HVTN), and the South African AIDS Vaccine Initiative (SAAVI). The vaccine being tested contains a weakened virus carrying only three of the nine HIV genes, thereby making it impossible for participants to become infected from the vaccine.

The NIAID press release stated that the objectives of HVTN 503 "are to determine whether the candidate vaccine can prevent HIV infection or, in those who do become infected, lower the level of HIV early on. Additionally, the new trial will determine if the vaccine, which is based on clade B HIV, has the potential to protect against the HIV clade C subtype prevalent in South Africa."

 At-a-Glance will track and report the progress of this trial as information becomes available.

NIAID Researchers Make Important Step in Search for an HIV Vaccine

On February 14, 2007, the National Institutes of Health announced that an AIDS vaccine research team at the National Institute of Allergy and Infectious Diseases (NIAID) has generated an atomic-level picture of an HIV surface protein being bound by an antibody that broadly neutralizes HIV.

The research team, led by Dr. Peter Kwong, visualized the binding of an antibody known as b12 to a specific piece of the HIV surface protein gp120. This piece of gp120 is somewhat unique among HIV proteins because it is not often mutated, which makes it an excellent target for a vaccine. This lack of mutation may be explained by another finding of the study; the same piece of gp120 that is bound by b12 also acts as the first point of contact between HIV and the CD4 receptor that the virus uses to enter cells, an essential step in the life cycle of HIV.

These developments may greatly advance the design of an HIV vaccine, which would be a powerful tool in the prevention and treatment of HIV/AIDS.

For more information about HIV vaccines:

- Read the AIDSinfo vaccine fact sheets, Preventive HIV Vaccines and Therapeutic HIV Vaccines.

- Visit the NIAID Vaccine Research Center Web site

Maraviroc to Receive Accelerated Review at an FDA Advisory Meeting on April 24, 2007

Maraviroc, a CCR5 antagonist, will receive accelerated review at a Food and Drug Administration (FDA) Advisory Meeting on April 24, 2007. Accelerated reviews are granted to potential therapies that could provide better options than current therapies. 

CCR5 is a protein found on the surface of certain immune cells that the HIV virus uses to enter the cell. CCR5 antagonists inhibit HIV from entering immune cells.

If approved, maraviroc will be the first CCR5 antagonist approved to treat HIV infection.