Contribution of the rev gene to the immunogenicity of DNA vaccines targeting the envelope glycoprotein of HIV.
BACKGROUND
The Rev protein of HIV plays a critical role in the export of viral mRNA from the nucleus to the cytoplasm of infected cells. This work examines the effect of introducing rev into a DNA vaccine encoding the Env protein of HIV, and compares the activity of env genes regulated by CMV versus CAG promoters.


METHODS
The HIV Env gp160 encoding gene with or without the rev gene was subcloned into a CMV promoter or a CAG promoter-driven expression plasmid. The Env protein expression of the plasmids was examined in vitro and the HIV-specific immunity was explored in BALB/c mice by an intramuscular route. The immune mice were intraperitoneally challenged with an HIV Env-expression vaccinia virus.


RESULTS
Results indicate that the CAG promoter induces significantly higher levels of Env expression, and better immune responses, than the CMV promoter. Incorporating the rev gene into these plasmids further boosts antigen expression and immunogenicity. Indeed, vaccination with the pCAGrev/env or pCMVrev/env plasmid resulted in 1000-fold lower viral load than that with pCMVenv when the mice were challenged with an Env-expressing vaccinia virus.


CONCLUSIONS
Incorporating rev into a DNA vaccine significantly increases the level of expression and immunogenicity of a co-expressed env gene, and that protective efficacy is further improved by utilizing a pCAG promoter.
Jounai
Nao
N
Department of Bacteriology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan.
Okuda
Kenji
K
Kojima
Yoshitsugu
Y
Toda
Yoshihiko
Y
Hamajima
Kenji
K
Ohba
Kenji
K
Klinman
Dennis
D
Xin
Ke-Qin
KQ
D000818:Animals; D000914:Antibodies, Viral; D002460:Cell Line; D003587:Cytomegalovirus / Q000235:genetics; D005260:Female; D018390:Gene Targeting; D015752:Genes, env; D015757:Genes, rev; D006678:HIV / Q000235:genetics*; D019302:HIV Envelope Protein gp160 / Q000235:genetics*; D007111:Immunity, Cellular; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014616:Vaccinia virus / Q000235:genetics
D000914:Antibodies, Viral; D019302:HIV Envelope Protein gp160; D019444:Vaccines, DNA