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. Author manuscript; available in PMC: 2021 Sep 8.

Published in final edited form as: Vaccine. 2017 Feb 16;36(22):3090–3100. doi: 10.1016/j.vaccine.2017.01.068

Figure 5. — Panel A: ELISA IgG antibody titers post third vaccine dose using plates coated with homologous antigen. EC₅₀ titers from individual animals (n=4 per group) were calculated using a sigmoidal dose-response, variable slope program (Graphpad Prism). The GMT + 95% CI is plotted for each group. Significant differences between groups are indicated by overlying horizontal bars on Figure 5A. At the same antigen dose levels of both 1 or 3 μg of EBOV GP, differences between groups immunized with formulations containing GPI-0100 showed significantly higher titers than formulations containing CoVaccine HT^™ (CoV HT) or Ribi. Differences between groups immunized with 9 μg GP and GPI-0100 or Ribi and with 9 μg GP and CoVaccine HT^™ or Ribi were also significant (p = 0.0191 for both comparisons). IgG titers in formulations containing CoVaccine HT^™ showed the only statistically significant dose response when comparing the 1 and 9 μg doses of vaccine. Differences between all other groups were not significant (p > 0.05). Panel B: Mean (n=6 per group) lymphocyte proliferation (stimulation index, SI) from immune splenocytes stimulated with homologous antigen in vitro, harvested at day 4 (n=3) or day 7 (n=3) post booster vaccination. Mean SI from mitogen (PHA) stimulated cultures varied in the range of 2.4–50. Mean SI in splenocyte cultures from adjuvant only immunized mice stimulated with GP was <1.7 in all cases. Significant differences between groups are indicated by overlying horizontal bars and showed significant differences between CoVaccine HT^™ and GPI-0100 adjuvanted formulations at the 1 and 9 μg GP dose levels. No other pairwise comparisons yielded significant differences. Panel C: Mean (n=3 per group) IFN-γ production in vitro from immune splenocytes stimulated with homologous antigen. Mean IFN-γ production from control (unstimulated) cultures was <0.35 ng/mL in all cases except the 1 μg GP/Ribi group, which had 0.97 ng/mL. Mean IFN-γ production in splenocyte cultures from adjuvant only immunized mice stimulated with GP was undetectable (<0.1 ng/mL) in all cases. Significant differences between groups are indicated by overlying horizontal bars and showed a significant difference only between GPI-0100 and Ribi adjuvanted formulations at the 9 μg GP dose level. No other pairwise comparisons yielded significant differences. Panel D: Mean (n=3 per group) IL-5 production in vitro from immune splenocytes stimulated with homologous antigen. Mean IL-5 production from control (unstimulated) cultures was undetectable (<0.1 ng/mL) in all cases. Mean IL-5 production in splenocyte cultures from adjuvant only immunized mice stimulated with GP was undetectable (<0.1 ng/mL) in all cases. Significant differences between various groups are indicated by overlying horizontal bars. No other pairwise comparisons yielded significant differences.

Figure 5. — Panel A: ELISA IgG antibody titers post third vaccine dose using plates coated with homologous antigen. EC₅₀ titers from individual animals (n=4 per group) were calculated using a sigmoidal dose-response, variable slope program (Graphpad Prism). The GMT + 95% CI is plotted for each group. Significant differences between groups are indicated by overlying horizontal bars on Figure 5A. At the same antigen dose levels of both 1 or 3 μg of EBOV GP, differences between groups immunized with formulations containing GPI-0100 showed significantly higher titers than formulations containing CoVaccine HT^™ (CoV HT) or Ribi. Differences between groups immunized with 9 μg GP and GPI-0100 or Ribi and with 9 μg GP and CoVaccine HT^™ or Ribi were also significant (p = 0.0191 for both comparisons). IgG titers in formulations containing CoVaccine HT^™ showed the only statistically significant dose response when comparing the 1 and 9 μg doses of vaccine. Differences between all other groups were not significant (p > 0.05). Panel B: Mean (n=6 per group) lymphocyte proliferation (stimulation index, SI) from immune splenocytes stimulated with homologous antigen in vitro, harvested at day 4 (n=3) or day 7 (n=3) post booster vaccination. Mean SI from mitogen (PHA) stimulated cultures varied in the range of 2.4–50. Mean SI in splenocyte cultures from adjuvant only immunized mice stimulated with GP was <1.7 in all cases. Significant differences between groups are indicated by overlying horizontal bars and showed significant differences between CoVaccine HT^™ and GPI-0100 adjuvanted formulations at the 1 and 9 μg GP dose levels. No other pairwise comparisons yielded significant differences. Panel C: Mean (n=3 per group) IFN-γ production in vitro from immune splenocytes stimulated with homologous antigen. Mean IFN-γ production from control (unstimulated) cultures was <0.35 ng/mL in all cases except the 1 μg GP/Ribi group, which had 0.97 ng/mL. Mean IFN-γ production in splenocyte cultures from adjuvant only immunized mice stimulated with GP was undetectable (<0.1 ng/mL) in all cases. Significant differences between groups are indicated by overlying horizontal bars and showed a significant difference only between GPI-0100 and Ribi adjuvanted formulations at the 9 μg GP dose level. No other pairwise comparisons yielded significant differences. Panel D: Mean (n=3 per group) IL-5 production in vitro from immune splenocytes stimulated with homologous antigen. Mean IL-5 production from control (unstimulated) cultures was undetectable (<0.1 ng/mL) in all cases. Mean IL-5 production in splenocyte cultures from adjuvant only immunized mice stimulated with GP was undetectable (<0.1 ng/mL) in all cases. Significant differences between various groups are indicated by overlying horizontal bars. No other pairwise comparisons yielded significant differences.