A New Cage-Like Particle Adjuvant Enhances Protection of Foot-and-Mouth Disease Vaccine

Figures

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  Figure 1. Selection of the infective dose of FMDV, serotype A. Groups of BALB/c mice (n = 4) were ip inoculated with 500 μL of 101.5TCID50, 102.5TCID50, or 103.5TCID50/mL of infectious FMDV A/Argentina/2001, and viremia was analyzed at 24, 48, and 72 hpi. (A) Percentage of infected animals at 24, 48, and 72 hpi and (B) percentage of surviving mice at 24, 48, 72, and 96 h after inoculation with infective FMDV.

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  Figure 2. Selection of iFMDV dose for vaccination of BALB/c mice. Groups of mice (n = 8) were vaccinated with 1, 0.5, 0.3, or 0.1 μg of iFMDV in PBS and challenged with infective virus after 21 dpv. (A) Percentages of protected animals on viral challenge. Group 0 corresponds to animals inoculated with PBS. Animals were considered protected if viremia was absent at 24 h post challenge. Protection percentages were calculated as 100× (number of vaccinated animals without viremia/number of vaccinated animals). (B) Antibodies against FMDV elicited by vaccination with different amounts of iFMDV measured by ELISA at 21 dpv.

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  Figure 3. Protection on viral challenge elicited by different vaccines. Groups of mice (n = 10) were vaccinated with iFMDV, ISPA-iFMDV, or a commercial FMD vaccine, and groups of mice (n = 4) were vaccinated with ISPA or PBS alone, and challenged with infective FMDV at 21 dpv. Protection was calculated as described for Figure 2. Results are representative of two independent experiments.

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  Figure 4. Antibodies against FMDV elicited by different vaccines in mice. FMDV specific antibody titers were measured by (A) liquid-phase ELISA at 14 and 21 dpv. Each bar represents the mean (n = 5) Ab titer ± SD in each group. (B) Isotype profile of vaccinated animals at 21 dpv. Data are expressed as the mean Ab titer ± SD. ***p < 0.001; **p < 0.01; *p < 0.05.

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  Figure 5. Cellular immune response in mice splenocytes at 21 dpv. Animals were vaccinated with iFMDV, ISPA-iFMDV, ISPA, or PBS. Splenocyte proliferative response after stimulation with iFMDV was measured by CFSE loss. Results are expressed as the difference (Δ%) between the percentage of proliferating splenocytes stimulated with inactivated virus and the percentage of proliferating splenocytes without stimuli. **p < 0.01; *p < 0.05.

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  Figure 6. Humoral response elicited in cattle by different vaccines. FMDV-specific antibody titers were measured by liquid-phase ELISA. (A) Each bar represents the mean Ab titer ± SEM (n = 4) at 15, 30, 48, and 76 dpv. (B) Isotype profiles at 30 dpv, expressed as mean Ab titers ± SD. *p < 0.05.

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  Figure 7. Cellular immune response in cattle. (A) Lymphocyte proliferative response after stimulation with iFMDV, A/Arg/2001 serotype, measured by CFSE loss. Differences (Δ%) were calculated as (% proliferating PBMCs stimulated with inactivated virus—% proliferating PBMCs without stimuli). (B) Percentages of CD8+/IFNγ+ or CD4+/IFNγ+ T cells in PBMCs of cattle immunized with iFMDV or iFMDV–ISPA, at 76 dpv. ***p < 0.001; **p < 0.01; *p < 0.05.