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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 responses in animals vaccinated with monovalent or trivalent DNA. Average IgG responses against rgp120IIIb in immunized. (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Average neutralizing activity, expressed as IC50, of diluted guinea pig serum (B) or purified rabbit IgG (D) from week 14 against pseudotype virus strains of clade A–D and CRF02_AG. Unrelated MLV pseudotype virus was included as non-specific HIV control in the guinea pig setup (red). IgG titers (C) and IC50 values (D) from syn.gp140Bx08 in the rabbit model are derived from Figure 1B,C.
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vaccines-01-00305-f002: Comparison of the immune responses in animals vaccinated with monovalent or trivalent DNA. Average IgG responses against rgp120IIIb in immunized. (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Average neutralizing activity, expressed as IC50, of diluted guinea pig serum (B) or purified rabbit IgG (D) from week 14 against pseudotype virus strains of clade A–D and CRF02_AG. Unrelated MLV pseudotype virus was included as non-specific HIV control in the guinea pig setup (red). IgG titers (C) and IC50 values (D) from syn.gp140Bx08 in the rabbit model are derived from Figure 1B,C.

Mentions: Guinea pig and rabbit groups were immunized with a trivalent mix encoding syn.gp140Bx08, syn.gp140ctl21 and syn.gp140ctl27 to facilitate heterotrimer formation (referred to as syn.gp140mix). Guinea pigs were also immunized with the same single DNA construct, syn.gp140Bx08, as used in rabbits in Figure 1. Monovalent and trivalent DNA immunizations demonstrated similar immunogenicity in guinea pigs (Figure 2A). In the rabbit model, the syn.gp140mix induced a higher fold increase in IgG response at w14 than syn.gp140Bx08 from Figure 1B (Figure 2C). Immune sera obtained week 14 from guinea pigs and rabbits were analyzed for neutralizing activity (Figure 2B,D, and Supplementary Table 1). Guinea pig sera were diluted and used directly in the TZMbl assay, whereas IgG had to be purified from the rabbit sera because of interference observed in some samples. Guinea pig sera and rabbit IgG were tested for NAbs against a panel of 13 or six different viruses, respectively. In the guinea pig model, syn.gp140mix tended to induce higher NAb titers to most viruses tested (Figure 2B) than monomeric syn.gp140Bx08, although this was not statistically significant (p = 0.054, Wilcoxon signed rank test). In the rabbit model, this tendency was less pronounced (Figure 2D). For both guinea pig sera and rabbit IgG, there was a large variation in neutralizing activity; however, the clade B viruses were the most sensitive to neutralization. Pseudotype virus expressing the unrelated murine leukemia virus (MLV) envelope was included as controls when testing guinea pigs sera and demonstrated no vaccine-induced unspecific effect (Figure 2B). Taken together, these results tended to favor the trivalent mix although broader neutralization could not be demonstrated in the rabbit model. However, since the trivalent mixture induced somewhat higher and broader neutralization in guinea pigs to most viruses and a somewhat higher cross-reacting antibody titer (anti-gp120IIIb) in rabbits, the syn.gp140mix was modified and used in further optimization experiments. In addition, the mixing approach has proven effective in other studies [48,49,50,51].


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 responses in animals vaccinated with monovalent or trivalent DNA. Average IgG responses against rgp120IIIb in immunized. (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Average neutralizing activity, expressed as IC50, of diluted guinea pig serum (B) or purified rabbit IgG (D) from week 14 against pseudotype virus strains of clade A–D and CRF02_AG. Unrelated MLV pseudotype virus was included as non-specific HIV control in the guinea pig setup (red). IgG titers (C) and IC50 values (D) from syn.gp140Bx08 in the rabbit model are derived from Figure 1B,C.
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Related In: Results  -  Collection

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

vaccines-01-00305-f002: Comparison of the immune responses in animals vaccinated with monovalent or trivalent DNA. Average IgG responses against rgp120IIIb in immunized. (A) guinea pigs (n = 4) and (C) rabbits (n = 4). Immunization time points are indicated with arrows. Average neutralizing activity, expressed as IC50, of diluted guinea pig serum (B) or purified rabbit IgG (D) from week 14 against pseudotype virus strains of clade A–D and CRF02_AG. Unrelated MLV pseudotype virus was included as non-specific HIV control in the guinea pig setup (red). IgG titers (C) and IC50 values (D) from syn.gp140Bx08 in the rabbit model are derived from Figure 1B,C.
Mentions: Guinea pig and rabbit groups were immunized with a trivalent mix encoding syn.gp140Bx08, syn.gp140ctl21 and syn.gp140ctl27 to facilitate heterotrimer formation (referred to as syn.gp140mix). Guinea pigs were also immunized with the same single DNA construct, syn.gp140Bx08, as used in rabbits in Figure 1. Monovalent and trivalent DNA immunizations demonstrated similar immunogenicity in guinea pigs (Figure 2A). In the rabbit model, the syn.gp140mix induced a higher fold increase in IgG response at w14 than syn.gp140Bx08 from Figure 1B (Figure 2C). Immune sera obtained week 14 from guinea pigs and rabbits were analyzed for neutralizing activity (Figure 2B,D, and Supplementary Table 1). Guinea pig sera were diluted and used directly in the TZMbl assay, whereas IgG had to be purified from the rabbit sera because of interference observed in some samples. Guinea pig sera and rabbit IgG were tested for NAbs against a panel of 13 or six different viruses, respectively. In the guinea pig model, syn.gp140mix tended to induce higher NAb titers to most viruses tested (Figure 2B) than monomeric syn.gp140Bx08, although this was not statistically significant (p = 0.054, Wilcoxon signed rank test). In the rabbit model, this tendency was less pronounced (Figure 2D). For both guinea pig sera and rabbit IgG, there was a large variation in neutralizing activity; however, the clade B viruses were the most sensitive to neutralization. Pseudotype virus expressing the unrelated murine leukemia virus (MLV) envelope was included as controls when testing guinea pigs sera and demonstrated no vaccine-induced unspecific effect (Figure 2B). Taken together, these results tended to favor the trivalent mix although broader neutralization could not be demonstrated in the rabbit model. However, since the trivalent mixture induced somewhat higher and broader neutralization in guinea pigs to most viruses and a somewhat higher cross-reacting antibody titer (anti-gp120IIIb) in rabbits, the syn.gp140mix was modified and used in further optimization experiments. In addition, the mixing approach has proven effective in other studies [48,49,50,51].

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