DNA vaccination of macaques by a full genome HIV-1 plasmid which produces noninfectious virus particles

In this study, we tried a DNA vaccination regime in rhesus macaques using a full genome HIV-1 plasmid. The HIV-I genome is under the control of its or iginal LTR promoter, but has a mutated zinc finger motif gene in the nucleo capsid region. Due to the lack of genomic RNA packaging, the plasmid produc es only noninfectious viral particles. We repeatedly injected four macaque monkeys intramuscularly with the naked DNA over a period of 40 weeks. To ev aluate the humoral and cell-mediated immunity provided by this DNA vaccinat ion, no other booster or other recombinant viral vectors were used. Immunol ogical responses against HIV-I were elicited in all of the vaccinated monke ys: stable anti-HIV-l Env antibodies were raised in two monkeys and CTL act ivities were induced in the other monkeys. The macaques were intravenously challenged at 54 weeks with 100 TCID5C of SHIV-NM-3rN, which possesses an e nvelope gene homologous to the one in the vaccinated plasmid. In all of the vaccinated macaques, the peak plasma viral loads induced by the challenge virus were two to three orders of magnitude lower than those of the naive c ontrols. These results suggest that a DNA vaccination regime with a full ge nome plasmid alone is potentially efficacious and provides a new possibilit y for the development of an AIDS vaccine, (C) 2000 Academic Press.