Figure 1. Study design and immunization schedule. Mice were primed 3 times with a pentavalent DNA vaccine in weeks 0, 2, and 4, followed by 2 pentavalent gp120 protein boosts in weeks 8 and 12. Either the DNA or protein pentavalent vaccine consisted of five HIV-1 Env gp120 immunogens from clades A (92UG037.8), B (92US715.6 and Bal), C (96ZM651), and E (93TH976.17). As a control, mice were immunized with empty pSW3891 vector primes followed by DP6-001 protein and adjuvant boosts. Additional controls included mice immunized with two full dose DP6-001 protein vaccine immunizations and adjuvant, in the absence of DNA priming. Al(OH)₃ and ISCOMATRIX™ adjuvant were tested individually as part of the protein boost. Follow-up experiments included 5 immunizations with DP6-001 protein ISCOMATRIX™ vaccine according to the established prime-boost schedule, with the first three immunizations at a 1/5 dose, and the final two immunizations at a full protein dose. A constant dose of ISCOMATRIX™ adjuvant was used for all immunizations. Time points of immunizations, and sample collections for different assays are indicated.