A DNA vaccines or immunogenic composition for providing an immune response against HIV without exhibiting pathogenicity in the immunized individual because of the disruption of the ability of the DNA molecules to encode for viral proteins critical in producing pathogenicity. The DNA molecule is derived by passaging a SHIV in order to develop a SHIV that exhibits an increased replication efficiency and increased pathogenicity. Following passaging, the highly virulent SHIV virus is rendered safe by disrupting one or more genes, such as the rt, int, and vif genes, as well as the 3' LTR.