Patients continue antiretroviral medications throughout the course of this study. Three groups of patients receive dose-escalation (0.5mg, 2mg or 4mg) intramuscular injections of DNA vaccine (D-GPEi) respectively, the other three groups of patients receive dose-escalation (3×10^7pfu, 1×10^8pfu or 3×10^8pfu) intradermal injections of MVA vaccine (M-GPE), two weeks post immunization of lower dose, if the vaccine is safe and well tolerant, the next dose of immunization will begin. After the maximum tolerated dose of DNA and MVA is identified, DNA prime/ MVA boosting will be tested in another two groups of patients. Lower or the maximum tolerated dose of D-GPEi was used at week 0 and 1, lower or the maximum tolerated dose of M-GPE was used at week 2 and 3, patients are monitored for safety 72 hours after each immunization. In addition, each patient records adverse events in a diary. Patients have regular physical exams, pregnancy tests, and blood drawn for virologic and immunologic assessments. The induction of HIV-specific responses will be measured.