Vectors used to create experimental HIV vaccines could do patients more harm than good by dampening the immune response to a natural infection, according to animal studies performed at the Wistar Institute in Philadelphia (Lin SW et al. J Clin Invest. 2007;117:3958-3970).
The findings suggest that recombinant adeno-associated virus (rAAV)
may undermine the immune system and should not be used for vaccine development.
Specifically, while rAAV properly induces HIV-specific T cells of the immune system, those cells are functionally impaired. In studies conducted in mice, HIV-specific T cells induced by the rAAV vector only poorly protected animals from subsequent infection, failed to secrete adequate levels of immune system–activating cytokines,
and displayed a severely impaired ability to proliferate.
Hampton T. Harmful HIV Carrier. JAMA. 2008;299(1):29. doi:10.1001/jama.2007.34