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Bolstering Components of the Immune Response Compromised by Prior Exposure to Adenovirus: Guided Formulation Development for a Nasal Ebola Vaccine.

Choi JH, Schafer SC, Freiberg AN, Croyle MA - Mol. Pharm. (2015)

Bottom Line: An amphiphilic polymer (F16, FW ∼39,000) significantly improved transgene expression in the presence of anti-Ad neutralizing antibodies (NAB) at concentrations of 5 times the 50% neutralizing dose (ND50).Multiparameter flow cytometry revealed that F16 induced significantly more polyfunctional antigen-specific CD8+ T cells simultaneously producing IFN-γ, IL-2, and TNF-α than other test formulations.These effects were not compromised by PEI.

View Article: PubMed Central - PubMed

Affiliation: †Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States.

ABSTRACT
The severity and longevity of the current Ebola outbreak highlight the need for a fast-acting yet long-lasting vaccine for at-risk populations (medical personnel and rural villagers) where repeated prime-boost regimens are not feasible. While recombinant adenovirus (rAd)-based vaccines have conferred full protection against multiple strains of Ebola after a single immunization, their efficacy is impaired by pre-existing immunity (PEI) to adenovirus. To address this important issue, a panel of formulations was evaluated by an in vitro assay for their ability to protect rAd from neutralization. An amphiphilic polymer (F16, FW ∼39,000) significantly improved transgene expression in the presence of anti-Ad neutralizing antibodies (NAB) at concentrations of 5 times the 50% neutralizing dose (ND50). In vivo performance of rAd in F16 was compared with unformulated virus, virus modified with poly(ethylene) glycol (PEG), and virus incorporated into poly(lactic-co-glycolic) acid (PLGA) polymeric beads. Histochemical analysis of lung tissue revealed that F16 promoted strong levels of transgene expression in naive mice and those that were exposed to adenovirus in the nasal cavity 28 days prior to immunization. Multiparameter flow cytometry revealed that F16 induced significantly more polyfunctional antigen-specific CD8+ T cells simultaneously producing IFN-γ, IL-2, and TNF-α than other test formulations. These effects were not compromised by PEI. Data from formulations that provided partial protection from challenge consistently identified specific immunological requirements necessary for protection. This approach may be useful for development of formulations for other vaccine platforms that also employ ubiquitous pathogens as carriers like the influenza virus.

No MeSH data available.


Related in: MedlinePlus

FormulationF16 improves the antigen specific antibody responsein mice with prior exposure to adenovirus. The average optical densityread from individual samples obtained from each treatment group arepresented to serve as a measure of relative antibody concentrationand data reported as average values ± the standard error of themean obtained from two separate experiments each containing 6 miceper treatment. The limit of detection for the assay is 0.01 absorbanceunit. **p < 0.01, one-way ANOVA, Bonferroni/Dunnpost hoc analysis.
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fig8: FormulationF16 improves the antigen specific antibody responsein mice with prior exposure to adenovirus. The average optical densityread from individual samples obtained from each treatment group arepresented to serve as a measure of relative antibody concentrationand data reported as average values ± the standard error of themean obtained from two separate experiments each containing 6 miceper treatment. The limit of detection for the assay is 0.01 absorbanceunit. **p < 0.01, one-way ANOVA, Bonferroni/Dunnpost hoc analysis.

Mentions: The F16 formulation improved the immune response in animalswithPEI to adenovirus as the number of GP-specific, IFN-γ-secretingmononuclear cells isolated from the spleen of these animals was notablyhigher than that from naive animals given unformulated vaccine (2,290± 51 SFCs/million MNCs, naive, vs 2,840 ± 110 SFCs/millionMNCs, PEI/F16, p < 0.05, Figure 7A). The number of antigen-specific IFN-γ-secreting mononuclearcells isolated from the BAL fluid of animals given the F16 formulationwas not statistically different from that found in naive animals givenunformulated vaccine (p = 0.07, Figure 7B). This trend was also observed with respect to the multifunctionalCD8+ T cell response as it also did not change with respectto that found in naive animals given unformulated vaccine (naive/unformulated,64.9 ± 4.88%, vs IN PEI/F16 (10 mg/mL), 60.0 ± 9.1%, p = 0.055; Figure 7C). Forty-twodays after immunization, the effector memory CD8+ T cellresponse was also evaluated in mice immunized with unformulated vaccineor the F16 preparation. The F16 formulation increased the memory responseby a factor of 3.3 from 0.28 ± 0.15% (unformulated) to 0.93 ±0.25% (F16, data not shown). Serum from animals with pre-existingimmunity to adenovirus that were immunized with the F16 preparationcontained 4 times more anti-Ebola glycoprotein antibodies than thatfrom animals given unformulated vaccine (Figure 8). Samples from these animals also contained 5 times more of theIgG1 isotype and notable levels of antigen-specific IgM antibodies.


Bolstering Components of the Immune Response Compromised by Prior Exposure to Adenovirus: Guided Formulation Development for a Nasal Ebola Vaccine.

Choi JH, Schafer SC, Freiberg AN, Croyle MA - Mol. Pharm. (2015)

FormulationF16 improves the antigen specific antibody responsein mice with prior exposure to adenovirus. The average optical densityread from individual samples obtained from each treatment group arepresented to serve as a measure of relative antibody concentrationand data reported as average values ± the standard error of themean obtained from two separate experiments each containing 6 miceper treatment. The limit of detection for the assay is 0.01 absorbanceunit. **p < 0.01, one-way ANOVA, Bonferroni/Dunnpost hoc analysis.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4525322&req=5

fig8: FormulationF16 improves the antigen specific antibody responsein mice with prior exposure to adenovirus. The average optical densityread from individual samples obtained from each treatment group arepresented to serve as a measure of relative antibody concentrationand data reported as average values ± the standard error of themean obtained from two separate experiments each containing 6 miceper treatment. The limit of detection for the assay is 0.01 absorbanceunit. **p < 0.01, one-way ANOVA, Bonferroni/Dunnpost hoc analysis.
Mentions: The F16 formulation improved the immune response in animalswithPEI to adenovirus as the number of GP-specific, IFN-γ-secretingmononuclear cells isolated from the spleen of these animals was notablyhigher than that from naive animals given unformulated vaccine (2,290± 51 SFCs/million MNCs, naive, vs 2,840 ± 110 SFCs/millionMNCs, PEI/F16, p < 0.05, Figure 7A). The number of antigen-specific IFN-γ-secreting mononuclearcells isolated from the BAL fluid of animals given the F16 formulationwas not statistically different from that found in naive animals givenunformulated vaccine (p = 0.07, Figure 7B). This trend was also observed with respect to the multifunctionalCD8+ T cell response as it also did not change with respectto that found in naive animals given unformulated vaccine (naive/unformulated,64.9 ± 4.88%, vs IN PEI/F16 (10 mg/mL), 60.0 ± 9.1%, p = 0.055; Figure 7C). Forty-twodays after immunization, the effector memory CD8+ T cellresponse was also evaluated in mice immunized with unformulated vaccineor the F16 preparation. The F16 formulation increased the memory responseby a factor of 3.3 from 0.28 ± 0.15% (unformulated) to 0.93 ±0.25% (F16, data not shown). Serum from animals with pre-existingimmunity to adenovirus that were immunized with the F16 preparationcontained 4 times more anti-Ebola glycoprotein antibodies than thatfrom animals given unformulated vaccine (Figure 8). Samples from these animals also contained 5 times more of theIgG1 isotype and notable levels of antigen-specific IgM antibodies.

Bottom Line: An amphiphilic polymer (F16, FW ∼39,000) significantly improved transgene expression in the presence of anti-Ad neutralizing antibodies (NAB) at concentrations of 5 times the 50% neutralizing dose (ND50).Multiparameter flow cytometry revealed that F16 induced significantly more polyfunctional antigen-specific CD8+ T cells simultaneously producing IFN-γ, IL-2, and TNF-α than other test formulations.These effects were not compromised by PEI.

View Article: PubMed Central - PubMed

Affiliation: †Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States.

ABSTRACT
The severity and longevity of the current Ebola outbreak highlight the need for a fast-acting yet long-lasting vaccine for at-risk populations (medical personnel and rural villagers) where repeated prime-boost regimens are not feasible. While recombinant adenovirus (rAd)-based vaccines have conferred full protection against multiple strains of Ebola after a single immunization, their efficacy is impaired by pre-existing immunity (PEI) to adenovirus. To address this important issue, a panel of formulations was evaluated by an in vitro assay for their ability to protect rAd from neutralization. An amphiphilic polymer (F16, FW ∼39,000) significantly improved transgene expression in the presence of anti-Ad neutralizing antibodies (NAB) at concentrations of 5 times the 50% neutralizing dose (ND50). In vivo performance of rAd in F16 was compared with unformulated virus, virus modified with poly(ethylene) glycol (PEG), and virus incorporated into poly(lactic-co-glycolic) acid (PLGA) polymeric beads. Histochemical analysis of lung tissue revealed that F16 promoted strong levels of transgene expression in naive mice and those that were exposed to adenovirus in the nasal cavity 28 days prior to immunization. Multiparameter flow cytometry revealed that F16 induced significantly more polyfunctional antigen-specific CD8+ T cells simultaneously producing IFN-γ, IL-2, and TNF-α than other test formulations. These effects were not compromised by PEI. Data from formulations that provided partial protection from challenge consistently identified specific immunological requirements necessary for protection. This approach may be useful for development of formulations for other vaccine platforms that also employ ubiquitous pathogens as carriers like the influenza virus.

No MeSH data available.


Related in: MedlinePlus