title: Modifying the HIV-1 env gp160 gene to improve pDNA vaccine-elicited cell-mediated immune responses.
abstract: Plasmid DNA (pDNA) vaccines are effective at eliciting immune responses in a wide variety of animal model systems, however, pDNA vaccines have generally been incapable of inducing robust immune responses in clinical trials. Therefore, to identify means to improve pDNA vaccine performance, we compared various post-transcriptional and post-translational genetic modifications for their ability to improve antigen-specific CMI responses. Mice vaccinated using a sub-optimal 100 mcg dose of a pDNA encoding an unmodified primary isolate HIV-1(6101) env gp160 failed to demonstrate measurable env-specific CMI responses. In contrast, significant env-specific CMI responses were seen in mice immunized with pDNA expression vectors encoding env genes modified by RNA optimization or codon optimization. Further modification of the RNA optimized env gp160 gene by the addition of (i) a simian retrovirus type 1 constitutive RNA transport element; (ii) a murine intracisternal A-particle derived RNA transport element; (iii) a tissue plasminogen activator protein signal leader sequences; (iv) a beta-catenin derived ubiquitination target sequence; or (v) a monocyte chemotactic protein-3 derived signal sequence failed to further improve the induction of env-specific CMI responses. Therefore, modification of the env gp160 gene by RNA or codon optimization alone is necessary for high-level rev-independent expression and results in robust env-specific CMI responses in immunized mice. Importantly, further modification(s) of the env gene to alter cellular localization or increase proteolytic processing failed to result in increased env-specific immune responses. These results have important implications for the design and development of an efficacious vaccine for the prevention of HIV-1 infection.
authors.affiliation: Wyeth Vaccines Research, Pearl River, NY 10965, United States.
authors.forename: Shakuntala
authors.initials: S
authors.lastname: Megati
authors.forename: Dorys
authors.initials: D
authors.lastname: Garcia-Hand
authors.forename: Sarah
authors.initials: S
authors.lastname: Cappello
authors.forename: Vidia
authors.initials: V
authors.lastname: Roopchand
authors.forename: Amjed
authors.initials: A
authors.lastname: Masood
authors.forename: Rong
authors.initials: R
authors.lastname: Xu
authors.forename: Amara
authors.initials: A
authors.lastname: Luckay
authors.forename: Siew-Yen
authors.initials: SY
authors.lastname: Chong
authors.forename: Margherita
authors.initials: M
authors.lastname: Rosati
authors.forename: Solomon
authors.initials: S
authors.lastname: Sackitey
authors.forename: David B
authors.initials: DB
authors.lastname: Weiner
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Felber
authors.forename: George N
authors.initials: GN
authors.lastname: Pavlakis
authors.forename: Zimra R
authors.initials: ZR
authors.lastname: Israel
authors.forename: Larry R
authors.initials: LR
authors.lastname: Smith
authors.forename: John H
authors.initials: JH
authors.lastname: Eldridge
authors.forename: Maninder K
authors.initials: MK
authors.lastname: Sidhu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Egan
mesh_terms: D016915:AIDS Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D000818:Animals; D003062:Codon / Q000235:genetics*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015483:HIV Antibodies / Q000097:blood; D019302:HIV Envelope Protein gp160 / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015658:HIV Infections / Q000276:immunology / Q000517:prevention & control*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D012313:RNA / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D016915:AIDS Vaccines; D003062:Codon; D015483:HIV Antibodies; D019302:HIV Envelope Protein gp160; D019444:Vaccines, DNA; D012313:RNA; D007371:Interferon-gamma