Modifying the HIV-1 env gp160 gene to improve pDNA vaccine-elicited cell-mediated immune responses.
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.
Megati
Shakuntala
S
Wyeth Vaccines Research, Pearl River, NY 10965, United States.
Garcia-Hand
Dorys
D
Cappello
Sarah
S
Roopchand
Vidia
V
Masood
Amjed
A
Xu
Rong
R
Luckay
Amara
A
Chong
Siew-Yen
SY
Rosati
Margherita
M
Sackitey
Solomon
S
Weiner
David B
DB
Felber
Barbara K
BK
Pavlakis
George N
GN
Israel
Zimra R
ZR
Smith
Larry R
LR
Eldridge
John H
JH
Sidhu
Maninder K
MK
Egan
Michael A
MA
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*
D016915:AIDS Vaccines; D003062:Codon; D015483:HIV Antibodies; D019302:HIV Envelope Protein gp160; D019444:Vaccines, DNA; D012313:RNA; D007371:Interferon-gamma