Advax-CpG Adjuvant Provides Antigen Dose-Sparing and Enhanced Immunogenicity for Inactivated Poliomyelitis Virus Vaccines

Figures

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  Figure 1. Advax-CpG adjuvant enhances neutralizing activity and long-term immunogenicity of commercial trivalent inactivated polio virus (TIPV) vaccine (IPOL, Sanofi-Pasteur). Female BALB/c mice (n = 3/group) received intramuscular (i.m.) immunizations at weeks 0, 3, 7 and 12 with IPOL vaccine (8 DU type 1, 1.6 DU type 2 and 6.4 DU type 3) alone or formulated with Advax or Advax-CpG adjuvants. Sera were collected at weeks 2, 4, 9, 13, 26, 30, 35 and 44 after the first immunization. Neutralization (NT) titers were determined against type 1—Brunhilde, type 2—MEF-1 and type 3—Saukett virus. Due to insufficient sera being available to run NT assays on individual mice, sera from each members of a group were assembled into a single pooled sample to run the NT assay, resulting in a single result for each serotype (A). Type-specific antibodies were determined by ELISA and OD values are shown as mean ± SD (B–D). The significance for ELISA results was analyzed by one-way ANOVA with the Kruskal–Wallis test and was indicated as * p < 0.05. Arrows indicate the immunization timing.

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  Figure 2. Dose-sparing effect of Advax and Advax-CpG adjuvant on an experimental TIPV vaccine (SSI). Female BALB/c mice (n = 9/group) received two i.m. immunizations 3 weeks apart with indicated dose of TIPV vaccine with (Grey and Black bars) or without (White bars) Advax or Advax-CpG. Serum neutralizing (NT) titers against type 1—Brunhilde, type 2—MEF-1 and type 3—Saukett were calculated using the Kärber method (Mean + SD). (A). Dose-sparing effect of Advax adjuvant for serotype 1 was further determined by ELISA (B). Antibody values are mean + SD with significance indicated as * p < 0.05, *** p < 0.001 or NS; not-significant compared with 10 DU antigen alone group using Mann–Whitney test.

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  Figure 3. Kinetics and longevity of SSI trivalent and monovalent IPV neutralization antibodies. Female BALB/c mice (n = 9/group) received two intramuscular immunizations 3 weeks apart with indicated dose of trivalent (A) or monovalent (B–D) IPV vaccine alone (red) or formulated with Advax-CpG (blue) or CpG (green). Sera collected at indicated time-points were analyzed by virus neutralization assay against type1—Brunhilde, type 2—MEF-1 or type 3—Saukett virus. Serum neutralizing titers were calculated using the Kärber method (Mean ± SD). Dotted line placed at minimum protection level. SSI—Monovalent Type 1 at antigen dose of 0.1 and 1 DU not shown as they were below detection limit.

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  Figure 4. Dose-sparing effect of Advax-CpG adjuvant on SSI Monovalent IPV measured by ELISA and virus neutralization assay. Female BALB/c mice (n = 9/group) received two intramuscular (i.m.) immunizations 3 weeks apart with 10 DU of monovalent IPV vaccine alone (white bars) or 1 DU or 0.1 DU IPV antigens with Advax-CpG adjuvant (black bars). Serum collected 2 weeks after the second immunization was analyzed by ELISA against each vaccine antigen: type 1—Brunhilde (A), type 2—MEF-1 (B) and type 3—Saukett (C). Antibody values are mean + SD with significance indicated as * p < 0.05, ** p < 0.01, *** p < 0.001 or NS; not-significant compared with 10 DU IPV vaccine alone group using the Mann–Whitney test.

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  Figure 5. Neutralization activity and immunogenicity of SSI trivalent inactivated polio virus vaccine in rats. Female Wistar rats weighing between 175 and 250 g, were immunized i.m. twice 3 weeks apart with SSI TIPV (type 1—10 U, type 2—2 U, type 3—9 DU) alone or formulated with Advax or Advax-CpG. Blood samples were collected at week 2 and 4 for measurement of total IgG by ELISA (A) and neutralization activity (B). Antibody values are mean + SD. Serum neutralizing was calculated using the Kärber method (Mean + SD). Significance was analyzed by one-way ANOVA with the Kruskal–Wallis test and was indicated as * p < 0.05. Body weights were recorded until 13 weeks after the first immunization (C).