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Hepatitis C VLPs delivered to dendritic cells by a TLR2 targeting lipopeptide results in enhanced antibody and cell-mediated responses.

Chua BY, Johnson D, Tan A, Earnest-Silveira L, Sekiya T, Chin R, Torresi J, Jackson DC - PLoS ONE (2012)

Bottom Line: Although many studies provide strong evidence supporting the development of HCV virus-like particle (VLP)-based vaccines, the fact that heterologous viral vectors and/or multiple dosing regimes are required to induce protective immunity indicates that it is necessary to improve their immunogenicity.While co-formulation of this lipopeptide with VLPs only resulted in marginal improvements in dendritic cell (DC) uptake, its ability to concomitantly induce DC maturation at very small doses is a feature not observed using VLPs alone or in the presence of an aluminium hydroxide-based adjuvant (Alum).These results suggest overall that the immunogenicity of HCV VLPs can be significantly improved by the addition of this novel adjuvant by targeting their delivery to DCs and could therefore constitute a viable vaccine strategy for the treatment of HCV.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia.

ABSTRACT
Although many studies provide strong evidence supporting the development of HCV virus-like particle (VLP)-based vaccines, the fact that heterologous viral vectors and/or multiple dosing regimes are required to induce protective immunity indicates that it is necessary to improve their immunogenicity. In this study, we have evaluated the use of an anionic self-adjuvanting lipopeptide containing the TLR2 agonist Pam(2)Cys (E(8)Pam(2)Cys) to enhance the immunogenicity of VLPs containing the HCV structural proteins (core, E1 and E2) of genotype 1a. While co-formulation of this lipopeptide with VLPs only resulted in marginal improvements in dendritic cell (DC) uptake, its ability to concomitantly induce DC maturation at very small doses is a feature not observed using VLPs alone or in the presence of an aluminium hydroxide-based adjuvant (Alum). Dramatically improved VLP and E2-specific antibody responses were observed in VLP+E(8)Pam(2)Cys vaccinated mice where up to 3 doses of non-adjuvanted or traditionally alum-adjuvanted VLPs was required to match the antibody titres obtained with a single dose of VLPs formulated with this lipopeptide. This result also correlated with significantly higher numbers of specific antibody secreting cells that was detected in the spleens of VLP+E(8)Pam(2)Cys vaccinated mice and greater ability of sera from these mice to neutralise the binding and uptake of VLPs by Huh7 cells. Moreover, vaccination of HLA-A2 transgenic mice with this formulation also induced better VLP-specific IFN-γ-mediated responses compared to non-adjuvanted VLPs but comparable levels to that achieved when coadministered with complete freund's adjuvant. These results suggest overall that the immunogenicity of HCV VLPs can be significantly improved by the addition of this novel adjuvant by targeting their delivery to DCs and could therefore constitute a viable vaccine strategy for the treatment of HCV.

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Related in: MedlinePlus

Induction of antibody secreting cells.BALB/c mice (n = 3) were inoculated with (100 µl) subcutaneously at the base of the tail with 20 µg of VLPs alone, pre-incubated with an equal volume of aluminium hydroxide (13 mg/ml) or 60 µg of E8Pam2Cys in saline on days 0, 21 and 56. Splenocytes were harvested on day 63 and frequencies of (A) VLP- or (B) E2-specific antibody secreting cells were enumerated in a B cell ELISPOT assay. Spot forming units representing the number of specific antibody-secreting cells in each animal is shown with horizontal bar indicating the average number of cells and standard deviation within each group.
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pone-0047492-g004: Induction of antibody secreting cells.BALB/c mice (n = 3) were inoculated with (100 µl) subcutaneously at the base of the tail with 20 µg of VLPs alone, pre-incubated with an equal volume of aluminium hydroxide (13 mg/ml) or 60 µg of E8Pam2Cys in saline on days 0, 21 and 56. Splenocytes were harvested on day 63 and frequencies of (A) VLP- or (B) E2-specific antibody secreting cells were enumerated in a B cell ELISPOT assay. Spot forming units representing the number of specific antibody-secreting cells in each animal is shown with horizontal bar indicating the average number of cells and standard deviation within each group.

Mentions: The hierarchical pattern of antibody responses induced by E8Pam2Cys and Alhydrogel was also confirmed by the numbers of specific antibody secreting cells that were detected in the spleens of vaccinated mice. Once again significantly higher numbers of cells secreting both HCV VLP (Figure 4A) or E2-specific antibodies (Figure 4B) were detected in animals that received HCV VLPs mixed with E8Pam2Cys than those that were inoculated with HCV VLPs alone or VLPs formulated with Alhydrogel.


Hepatitis C VLPs delivered to dendritic cells by a TLR2 targeting lipopeptide results in enhanced antibody and cell-mediated responses.

Chua BY, Johnson D, Tan A, Earnest-Silveira L, Sekiya T, Chin R, Torresi J, Jackson DC - PLoS ONE (2012)

Induction of antibody secreting cells.BALB/c mice (n = 3) were inoculated with (100 µl) subcutaneously at the base of the tail with 20 µg of VLPs alone, pre-incubated with an equal volume of aluminium hydroxide (13 mg/ml) or 60 µg of E8Pam2Cys in saline on days 0, 21 and 56. Splenocytes were harvested on day 63 and frequencies of (A) VLP- or (B) E2-specific antibody secreting cells were enumerated in a B cell ELISPOT assay. Spot forming units representing the number of specific antibody-secreting cells in each animal is shown with horizontal bar indicating the average number of cells and standard deviation within each group.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3472981&req=5

pone-0047492-g004: Induction of antibody secreting cells.BALB/c mice (n = 3) were inoculated with (100 µl) subcutaneously at the base of the tail with 20 µg of VLPs alone, pre-incubated with an equal volume of aluminium hydroxide (13 mg/ml) or 60 µg of E8Pam2Cys in saline on days 0, 21 and 56. Splenocytes were harvested on day 63 and frequencies of (A) VLP- or (B) E2-specific antibody secreting cells were enumerated in a B cell ELISPOT assay. Spot forming units representing the number of specific antibody-secreting cells in each animal is shown with horizontal bar indicating the average number of cells and standard deviation within each group.
Mentions: The hierarchical pattern of antibody responses induced by E8Pam2Cys and Alhydrogel was also confirmed by the numbers of specific antibody secreting cells that were detected in the spleens of vaccinated mice. Once again significantly higher numbers of cells secreting both HCV VLP (Figure 4A) or E2-specific antibodies (Figure 4B) were detected in animals that received HCV VLPs mixed with E8Pam2Cys than those that were inoculated with HCV VLPs alone or VLPs formulated with Alhydrogel.

Bottom Line: Although many studies provide strong evidence supporting the development of HCV virus-like particle (VLP)-based vaccines, the fact that heterologous viral vectors and/or multiple dosing regimes are required to induce protective immunity indicates that it is necessary to improve their immunogenicity.While co-formulation of this lipopeptide with VLPs only resulted in marginal improvements in dendritic cell (DC) uptake, its ability to concomitantly induce DC maturation at very small doses is a feature not observed using VLPs alone or in the presence of an aluminium hydroxide-based adjuvant (Alum).These results suggest overall that the immunogenicity of HCV VLPs can be significantly improved by the addition of this novel adjuvant by targeting their delivery to DCs and could therefore constitute a viable vaccine strategy for the treatment of HCV.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia.

ABSTRACT
Although many studies provide strong evidence supporting the development of HCV virus-like particle (VLP)-based vaccines, the fact that heterologous viral vectors and/or multiple dosing regimes are required to induce protective immunity indicates that it is necessary to improve their immunogenicity. In this study, we have evaluated the use of an anionic self-adjuvanting lipopeptide containing the TLR2 agonist Pam(2)Cys (E(8)Pam(2)Cys) to enhance the immunogenicity of VLPs containing the HCV structural proteins (core, E1 and E2) of genotype 1a. While co-formulation of this lipopeptide with VLPs only resulted in marginal improvements in dendritic cell (DC) uptake, its ability to concomitantly induce DC maturation at very small doses is a feature not observed using VLPs alone or in the presence of an aluminium hydroxide-based adjuvant (Alum). Dramatically improved VLP and E2-specific antibody responses were observed in VLP+E(8)Pam(2)Cys vaccinated mice where up to 3 doses of non-adjuvanted or traditionally alum-adjuvanted VLPs was required to match the antibody titres obtained with a single dose of VLPs formulated with this lipopeptide. This result also correlated with significantly higher numbers of specific antibody secreting cells that was detected in the spleens of VLP+E(8)Pam(2)Cys vaccinated mice and greater ability of sera from these mice to neutralise the binding and uptake of VLPs by Huh7 cells. Moreover, vaccination of HLA-A2 transgenic mice with this formulation also induced better VLP-specific IFN-γ-mediated responses compared to non-adjuvanted VLPs but comparable levels to that achieved when coadministered with complete freund's adjuvant. These results suggest overall that the immunogenicity of HCV VLPs can be significantly improved by the addition of this novel adjuvant by targeting their delivery to DCs and could therefore constitute a viable vaccine strategy for the treatment of HCV.

Show MeSH
Related in: MedlinePlus