Activation of HIV-1-specific immune responses to an HIV-1 vaccine constructed from a replication-defective adenovirus vector using various combinations of immunization protocols

We constructed a recombinant replication defective adenovirus vector contai ning the env gene (Ad-Bal) derived from macrophage-trophic HIV-1 (HIV-1 Bal ). We then immunized mice with this vector using several administration rou tes and protocols, and examined the immune response. When the Ad-Bal viral vector (over 1 x 10(7) pfu) was injected subcutaneously, both humoral and c ell-mediated immunities were induced. However, immune response induced by t he Ad-Bal vector alone was weaker than that induced by the recombinant vacc inia viral vector. We then employed the following three immunization protoc ols: (1) DNA vaccination followed by immunization with the Ad-Bal; (2) vacc ination using the Ad-Bal vector followed by DNA vaccination; and (3) DNA va ccination followed by Ad-Bal infection and passive transfer of dendritic ce lls (DCs) infected with the Ad-Bal. Among the three protocols, the last gav e the strongest humoral and cell-mediated immunity. These results suggest t hat the combination of DNA vaccination, Ad-Bal vector infection and passive transfer of Ad-Bal-infected DCs can induce strong immunity against HIV-1 B al.