Preventive anti-HIV vaccines

The devastation caused by the HIV pandemic will probably not be quelled until a safe and effective vaccine has been developed that is also affordable and available in the developing countries where the impact of this virus is most severe. Considerable progress has been made over the past several years in the search for a vaccine against HIV: roughly 30 different types are currently being investigated in phase I/III clinical trials. Major scientific challenges nonetheless still remain. An ideal vaccine would elicit both neutralizing antibodies and cytotoxic T lymphocytes (CTL) and, perhaps, mucosal immune response. The precise correlates of immunity have not been defined. Recombinant live vector-based vaccines, lipopeptides, and plasmid DNA have all been shown to induce CTL. The different forms of prime-boost vaccine strategies currently being tested in numerous clinical trials provide reasons for hope.