Compositions induce the activation of dendritic cells comprising a polynucleotide, such as viruses, RNA, DNA, plasmid DNA, or derivatives thereof and at least one block copolymer of alkylethers. The present invention further relates to compositions for inducing the activation of dendritic cells wherein the block copolymers are PLURONIC F127 and L61. More particular, the compositions comprise block copolymers PLURONIC F127/PLURONIC L61. The invention also relates to methods of inducing the activation of dendritic cells in animals comprising administering the compositions of the invention. Additionally, the present invention relates to methods of increasing the immune response of animals comprising administering the compositions of the present invention.