The question of whether or not to continue to pursue the development of T-cell-based HIV-1 vaccines has been a source of controversy following last year’s widely publicized failure of the field’s most promising candidate, a vaccine developed by Merck known as V520.
Now a study led by investigators at Beth Israel Deaconess Medical Center (BIDMC) provides the proof-of-concept that a T-cell-based strategy remains a viable course to follow. Described in today’s Advance On-line Publication of Nature, the study showed that an improved regimen using two distinct adenovirus vectors – rAd26 prime/rAd5 boost – and expressing the simian immunodeficiency virus (SIV) Gag protein, resulted in potent T-cell immune responses leading to long-term immune control of an SIV challenge in monkeys. The findings demonstrate for the first time using this stringent animal model that such a vaccine may be effective in the fight against AIDS.
“This is a controversial field right now,” says the study’s lead scientist Dan Barouch, MD, PhD, Principal Investigator of the NIH-sponsored Integrated Preclinical/Clinical AIDS Vaccine Development (IPCAVD) program, who is working to develop new HIV-1 vaccine candidates. “Despite the disappointing setbacks in HIV-1 vaccine development this past year, our findings suggest that we’re not at the end of the road when it comes to T-cell vaccines. Our data show that T-cell vaccines that elicit greater magnitude, breadth, and quality of immune responses as compared with the Merck vaccine can result in improved protection in the rhesus monkey model of AIDS.”