Titers of anti-HBs antibodies (total IgG) in sera taken at various times from Aotus monkeys immunized at 0 and 8 weeks with an HBsAg-expressing DNA vaccine (400 µg pCMVA-S) or with HBsAg protein (10 µg), and then with HBsAg at 16 weeks. The DNA vaccines were given by one of eight methods: (D) IM in saline with needle and syringe or (E) Biojector; (G) IM associated with CellFECTIN with needle and syringe or (H) Biojector; (B) ID in saline with needle and syringe, (C) ID or (I) IM plus E. coli DNA (100 µg) or (F) a combination of ID and IM/Biojector. Control animals received HBsAg (10 µg) with alum for all three immunizations (A). Filled circles and black lines represent the group mean (n = 4). Open circles and gray lines indicate the values obtained for individual animals.