Fig. 1. Antibody responses in pigs vaccinated with the experimental foot-and-mouth disease vaccine with an ISA 201 oil adjuvant. (A) PI values of type O SP-enzyme-linked immunosorbent assay (ELISA) from sera of pigs vaccinated with 2 mL of vaccine. (B) PI values of type O SP-ELISA from sera of pigs vaccinated with 1 mL of vaccine. (C) PI values of type O SP-ELISA from sera of pigs vaccinated twice with 1 mL of vaccine. (D) VN titers to O/Andong/SKR/2010 in sera of pigs vaccinated with 2 mL of vaccine. (E) VN titers to O/Andong/SKR/2010 in sera of pigs vaccinated with 1 mL of vaccine. (F) VN titers to O/Andong/SKR/2010 in sera of pigs vaccinated twice with 1 mL of vaccine. (G) Antibody-positive rate (%) for type O in pigs vaccinated with 2 mL of vaccine. (H) Antibody-positive rate (%) for type O in pigs vaccinated with 1 mL of vaccine. (I) Antibody-positive rate (%) for type O in pigs vaccinated twice with 1 mL of vaccine. The antibody-positive rate was applied based on positive cutoff with O-SP ELISA (PI > 50) and VNT (> 1:16 for positive baseline and 1:45 for protectable level). Twenty pigs were included in this study. Black arrows indicate second vaccination (boosting). PI, percent inhibition value in SP-ELISA; VN, virus neutralizing; SP antibody, antibody against structural protein in SP-ELISA; AD, O/Andong/SKR/2010; JC, O/Jincheon/SKR/2014; VN-AD, virus neutralizing titer against O/Andong/SKR/2010; VN-JC, virus neutralizing titer against O/Jincheon/SKR/2014. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001.