Contribution of the rev gene to the immunogenicity of DNA vaccines targeting the envelope glycoprotein of HIV

✍ Scribed by Nao Jounai; Kenji Okuda; Yoshitsugu Kojima; Yoshihiko Toda; Kenji Hamajima; Kenji Ohba; Dennis Klinman; Dr Ke-Qin Xin

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 228 KB
• Volume: 5
• Category: Article
• ISSN: 1099-498X
• DOI: 10.1002/jgm.391

✦ Synopsis

Abstract

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. Copyright © 2003 John Wiley & Sons, Ltd.