The team, led by Ronald S. Veazey, professor of pathology and chair of the Division of Comparative Pathology at the Tulane National Primate Research Center, successfully used vaginal gels containing the fusion inhibitory peptide T-1249 to protect rhesus macaque monkeys against vaginal transmission of multiple strains of simian/human HIV (SHIV). Their report was published online on July 21, 2008 in the Proceedings of the National Academy of Sciences.
The study details the gel's success in protecting macaques from infection by three different strains of SHIV.
"Here we have shown that the vaginal application of gel-formulated T-1249 can protect rhesus macaques from infection by three different SHIV challenge viruses," say the researchers. "The protection we observed was dose-dependent, and at the higher concentration, robust, in that all the test animals resisted infection."
Fusion inhibitors such as T-1249 operate to inhibit infection by preventing glycoprotein molecules on HIV particles from binding to their receptors on the surface of the immune cell. The T-1249 peptide is a fusion inhibitor that targets one of the main cellular receptors that HIV uses to infect cells in the mucosal surface. A major advantage of T-1249 over other compounds is that it targets a receptor common to most strains of HIV.
The team concludes that vaginal microbicide containing fusion inhibitors remain a potential method for protecting women against infection by HIV type 1 during sexual intercourse.
The researchers caution: "Whether T-1249 could be developed as a practical microbicide will depend on whether it can be successfully formulated at a reasonable cost."
Protection against HIV in the real world is also very challenging because of the ever-increasing number of different HIV strains in circulation. "An effective microbicide formulation is, therefore, likely to require the coformulation of more than one entry inhibitor," say the authors.
The research was funded by grants from the National Institutes of Health and Bristol-Meyers Squibb.