NIAID's Strategic Program for Innovative Research on AIDS Treatment (SPIRAT) is conducting tests on a new type of therapeutic vaccine that may help boost the immune systems of HIV-infected individuals. This vaccine works by injecting non-infectious HIV genes into a patient's muscle. In preclinical studies in rodents and non-human primates, both antibody and cellular immune responses were stimulated by the injection of viral genes. It is hoped that when this vaccine causes the person's own cells to make HIV proteins, the immune system may begin producing antibodies and killer T-cells to fight HIV. Injection of DNA comprising the env and rev genes gives the immune system multiple targets for attack. Other studies are investigating delivery of viral genes into the host, using viral vectors.