It's the first time that a so-called DNA vaccine has squared off against HIV in chimps. Every pathogen has a unique set of genes, some of which set off ''alarms'' in a host's body. Those alarms cause the host to create immune responses that will try to destroy the disease or toxin. Johnston theorizes that if the specific gene that triggers the alarm could be separated from the rest of the pathogen, administering the gene to humans would give them the ability to create antibodies to the pathogen. Gene vaccinations offer several improvements over conventional ones.
Some traditional immunizations require booster shots.
And because with gene vaccinations the whole disease is not administered, the subject will not get ill - another downside to conventional shots, Johnston said. Because only a few genes prompt an immune response, the key to the process is finding the right gene.