Cytokine-induced augmentation of DNA vaccine-elicited SIV-specific immunity in rhesus monkeys

Plasmid DNA vaccination has recently emerged as a promising approach to elicit HIV- and SIV-specific humoral and cellular immune responses. However, the magnitude of immune responses induced by DNA vaccines alone has not been sufficient to protect primates against pathogenic lentivirus challenges. We investigated the ability of an IL-2/lg cytokine fusion protein and a plasmid expressing IL-2/lg to augment immune responses in rhesus monkeys induced by DNA vaccines encoding SIV gag and HIV-1 env 89.6P. We showed that both IL-2/lg protein and IL-2/lg plasmid augment DNA vaccine-elicited antibody and CTL responses. The most consistent and dramatic augmentation was observed using the IL-2/lg plasmid.