A Double-Blind Randomized Phase I Clinical Trial Targeting ALVAC-HIV Vaccine to Human Dendritic Cells

targeting of human dendritic cells (DC) would enhance the immune response compared to either conventional intramuscular or intradermal injections of the vaccine alone. transfected DC at months 0, 1, 3 and 6. All vaccine delivery routes were well tolerated. Binding antibodies were observed to both the ALVAC vector and HIV-1 gp160 proteins. Modest cellular responses were observed in 2/7 individuals in the DC arm and 1/8 in the IM arm as determined by IFN-γ ELISPOT. Proliferative responses were most frequent in the DC arm where 4/7 individuals had measurable responses to multiple HIV-1 antigens. Loading DC after maturation resulted in lower gene expression, but overall better responses to both HIV-1 and control antigens, and were associated with better IL-2, TNF-α and IFN-γ production. transfected DC proved to be safe. The DC arm was most immunogenic. Proliferative immune responses were readily detected with only modest cytotoxic CD8 T cell responses. Loading mature DC with the live viral vaccine induced stronger immune responses than loading immature DC, despite increased transgene expression with the latter approach. Volunteers who received the autologous vaccine loaded mature DC developed a broader and durable immune response compared to those vaccinated by conventional routes