A consortium of leading vaccine researchers at Emory University and partner institutions has received a National Institutes of Health (NIH) grant aimed at developing an effective HIV/AIDS vaccine. The five-year program project grant of more than $26 million from the National Institute of Allergy and Infectious Diseases (NIAID), part of the NIH, will fund the Emory Consortium for AIDS Vaccine Research in Nonhuman Primates. The research will be conducted primarily at the Yerkes National Primate Research Center at Emory.

"Developing a safe and effective preventive HIV/AIDS vaccine is still a critical part of the fight against this challenging disease that affects more than 30 million people worldwide," says Eric Hunter, PhD, who will lead the consortium. "With the vast experience of Emory's vaccine researchers and our partners, I'm confident we can make significant strides in developing a better HIV vaccine." Hunter is a member of the Emory Vaccine Center, a co-director of the Emory Center for AIDS Research, a professor of pathology and laboratory medicine at Emory University School of Medicine, and a Georgia Research Alliance Eminent Scholar.

The researchers will study how to develop a vaccine that can prevent the earliest stages of mucosal infection from simian immunodeficiency virus (SIV) in nonhuman primate models. SIV is similar to HIV in humans. The series of research projects is expected to provide a better understanding of how SIV is transmitted sexually and the specific immune responses HIV vaccines must generate in humans to block infection at mucosal sites, prevent the establishment of systemic infection, or dramatically reduce the pathogenic effects of infection.

The consortium's work will build on recent significant discoveries in the AIDS vaccine field. A vaccine trial in Thailand (RV144) completed in 2009 showed a modest degree of protection against HIV in humans. The results gave the vaccine research community hope that a vaccine could elicit antibodies that could at least moderately protect against HIV infection. In order to develop a more effective vaccine, however, researchers need to further explore the specific aspects of the immune response (referred to as correlates of immunity) in animal models as well as in human clinical trials, Hunter explains.

More than 90 percent of all HIV infections worldwide occur via mucous membranes, predominantly through sexual contact. In order to develop an effective vaccine, scientists must understand the viral-host interaction during the initial time of mucosal infection.

"By the time HIV-infected individuals begin experiencing the symptoms of acute HIV infection, this critical time of opportunity has passed," says Rama Amara, PhD, co-principal investigator of the consortium and a researcher at the Emory Vaccine Center and Yerkes Research Center. "Rhesus macaque monkeys provide an effective model for studying mucosal viral infection and ways to stimulate an early protective immune response."

Researchers agree that a successful HIV vaccine will likely need to elicit both effective T-cell and antibody responses. The Emory consortium will work to enhance the quality of antibody responses to HIV infection, building on recent Emory discoveries led by Amara and consortium member Bali Pulendran, PhD, using adjuvants to successfully enhance the effectiveness of vaccines against SIV infection.

Important follow-up questions the team will address include what kind of antigens and delivery system are needed to elicit protective antibodies, where should vaccines be delivered in the body, and how do adjuvants convert a poorly protective vaccine into one that fully protects against infection by the virus?

Source:
Holly Korschun
Emory University