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Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques.

Borggren M, Vinner L, Andresen BS, Grevstad B, Repits J, Melchers M, Elvang TL, Sanders RW, Martinon F, Dereuddre-Bosquet N, Bowles EJ, Stewart-Jones G, Biswas P, Scarlatti G, Jansson M, Heyndrickx L, Grand RL, Fomsgaard A - Vaccines (Basel) (2013)

Bottom Line: Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed.Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity.It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology Diagnostics and Virology, Statens Serum Institut, Copenhagen 2300, Denmark.

ABSTRACT
HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb). We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

No MeSH data available.


Related in: MedlinePlus

Comparison of the immune response in vaccinated guinea pigs (A,B) and rabbits (C,D) with plasmid DNA encoding syn.gp140mix or syn.gp140mix modified. Average IgG response against recombinant gp120IIIb (rgp120IIIb) in immunized (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Asterisk indicates significant difference between the two immunization groups (* p < 0.05, ** p < 0.01, two-way ANOVA). Average neutralizing activity, expressed as IC50, of (B) diluted guinea pig serum or (D) purified rabbit IgG from week 14 animal sera against pseudotype virus strains of clade A–D and CRF02_AG. Amphotropic murine leukemia virus (MLV) pseudotype virus was included as control for the non-specific activity in experiments with guinea pig serum (red). Results from syn.gp140mix immunizations were derived from Figure 2.
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vaccines-01-00305-f004: Comparison of the immune response in vaccinated guinea pigs (A,B) and rabbits (C,D) with plasmid DNA encoding syn.gp140mix or syn.gp140mix modified. Average IgG response against recombinant gp120IIIb (rgp120IIIb) in immunized (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Asterisk indicates significant difference between the two immunization groups (* p < 0.05, ** p < 0.01, two-way ANOVA). Average neutralizing activity, expressed as IC50, of (B) diluted guinea pig serum or (D) purified rabbit IgG from week 14 animal sera against pseudotype virus strains of clade A–D and CRF02_AG. Amphotropic murine leukemia virus (MLV) pseudotype virus was included as control for the non-specific activity in experiments with guinea pig serum (red). Results from syn.gp140mix immunizations were derived from Figure 2.

Mentions: Both guinea pigs and rabbits were immunized with the modified DNA constructs, syn.gp140mixSOSIP.R6-IZ-H8. The guinea pigs demonstrated specific IgG after the initial immunization which was boosted upon re-immunizations; however, the modified construct, syn.gp140mix SOSIP.R6-IZ-H8, induced significantly lower titers of antibodies when compared to non-modified syn.gp140mix, as per Figure 2A (compared in Figure 4A). Interestingly, vaccination with syn.gp140mix SOSIP.R6-IZ-H8 generated a statistically significant higher neutralizing activity than syn.gp140mix in the guinea pigs (p = 0.021, Wilcoxon signed rank test) despite the lower ELISA titers (Figure 4B, and Supplementary Table 1). However, the more potent neutralizing activity also included non-specific neutralization since a MLV pseudotype virus was also neutralized at high dilutions of guinea pig syn.gp140mix SOSIP.R6-IZ-H8 antisera. This unspecific neutralization was not seen with the non-modified syn.gp140mix in Figure 2B. Immunization of rabbits with the same construct resulted in lower antibody titers for syn.gp140mix SOSIP.R6-IZ-H8, as compared with non-modified construct in Figure 2C (compared in Figure 4C), and similarly, as seen with guinea pig sera. Though, in the rabbit model the two constructs yielded similar neutralizing activity for the six different viruses tested (compared in Figure 4D, and Supplementary Table 1). Only two of the six viruses used could be neutralized to 50% by syn.gp140mix SOSIP.R6-IZ-H8 antisera at the IgG concentrations tested, and they were both clades B pseudotype virus.


Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques.

Borggren M, Vinner L, Andresen BS, Grevstad B, Repits J, Melchers M, Elvang TL, Sanders RW, Martinon F, Dereuddre-Bosquet N, Bowles EJ, Stewart-Jones G, Biswas P, Scarlatti G, Jansson M, Heyndrickx L, Grand RL, Fomsgaard A - Vaccines (Basel) (2013)

Comparison of the immune response in vaccinated guinea pigs (A,B) and rabbits (C,D) with plasmid DNA encoding syn.gp140mix or syn.gp140mix modified. Average IgG response against recombinant gp120IIIb (rgp120IIIb) in immunized (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Asterisk indicates significant difference between the two immunization groups (* p < 0.05, ** p < 0.01, two-way ANOVA). Average neutralizing activity, expressed as IC50, of (B) diluted guinea pig serum or (D) purified rabbit IgG from week 14 animal sera against pseudotype virus strains of clade A–D and CRF02_AG. Amphotropic murine leukemia virus (MLV) pseudotype virus was included as control for the non-specific activity in experiments with guinea pig serum (red). Results from syn.gp140mix immunizations were derived from Figure 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494233&req=5

vaccines-01-00305-f004: Comparison of the immune response in vaccinated guinea pigs (A,B) and rabbits (C,D) with plasmid DNA encoding syn.gp140mix or syn.gp140mix modified. Average IgG response against recombinant gp120IIIb (rgp120IIIb) in immunized (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Asterisk indicates significant difference between the two immunization groups (* p < 0.05, ** p < 0.01, two-way ANOVA). Average neutralizing activity, expressed as IC50, of (B) diluted guinea pig serum or (D) purified rabbit IgG from week 14 animal sera against pseudotype virus strains of clade A–D and CRF02_AG. Amphotropic murine leukemia virus (MLV) pseudotype virus was included as control for the non-specific activity in experiments with guinea pig serum (red). Results from syn.gp140mix immunizations were derived from Figure 2.
Mentions: Both guinea pigs and rabbits were immunized with the modified DNA constructs, syn.gp140mixSOSIP.R6-IZ-H8. The guinea pigs demonstrated specific IgG after the initial immunization which was boosted upon re-immunizations; however, the modified construct, syn.gp140mix SOSIP.R6-IZ-H8, induced significantly lower titers of antibodies when compared to non-modified syn.gp140mix, as per Figure 2A (compared in Figure 4A). Interestingly, vaccination with syn.gp140mix SOSIP.R6-IZ-H8 generated a statistically significant higher neutralizing activity than syn.gp140mix in the guinea pigs (p = 0.021, Wilcoxon signed rank test) despite the lower ELISA titers (Figure 4B, and Supplementary Table 1). However, the more potent neutralizing activity also included non-specific neutralization since a MLV pseudotype virus was also neutralized at high dilutions of guinea pig syn.gp140mix SOSIP.R6-IZ-H8 antisera. This unspecific neutralization was not seen with the non-modified syn.gp140mix in Figure 2B. Immunization of rabbits with the same construct resulted in lower antibody titers for syn.gp140mix SOSIP.R6-IZ-H8, as compared with non-modified construct in Figure 2C (compared in Figure 4C), and similarly, as seen with guinea pig sera. Though, in the rabbit model the two constructs yielded similar neutralizing activity for the six different viruses tested (compared in Figure 4D, and Supplementary Table 1). Only two of the six viruses used could be neutralized to 50% by syn.gp140mix SOSIP.R6-IZ-H8 antisera at the IgG concentrations tested, and they were both clades B pseudotype virus.

Bottom Line: Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed.Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity.It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology Diagnostics and Virology, Statens Serum Institut, Copenhagen 2300, Denmark.

ABSTRACT
HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb). We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

No MeSH data available.


Related in: MedlinePlus