Figure 3.
A-3A and A-HSP70 mediated a long-lasting memory response in mice. C57BL/6 mice were administered with oil emulsion-free test vaccines, including A-3A antigen alone, A-HSP70 antigen alone, or combined A-3A and A-HSP70 antigens based on their positive control composition. The negative control group received PBS in the same volume as the vaccine. A positive control group received 1.5 μg (1/10 dose for cattle and pig use) of naïve A antigen, without (w/o) oil emulsion, 10% Al(OH)3, and 15 μg Quil-A. Briefly, vaccination was performed twice at a 35-day interval. The mice were vaccinated intramuscularly in the thigh muscle. Later, at 84 dpv or 168 dpv, the mice were challenged with FMDV (100 LD50 A/Malay-97, SEA topotype) by intraperitoneal injection. Survival rates and body weights were monitored for 7 dpc. In addition, serum sampled from mice at 0, 7, 14, 28, 56, 84, and 168 dpv was analyzed via SP A ELISA and VN assay. (A–G) represent: (A) the strategy for this study; (B) antibody titers by SP A ELISA; (C) VN titers; (D) survival rate at 84 dpv challenge; (E) changes of body weight at 84 dpv challenge; (F) survival rate at 168 dpv challenge; (G) changes of body weight at 168 dpv challenge. The data represent the means ± SEM of triplicate measurements (n = 5/group). Statistical analyses were performed using two-way ANOVA with Bonferroni correction and a one-way ANOVA followed by a Tukey’s post-hoc test. * p < 0.05; ** p < 0.01; *** p < 0.001; ns, not significant. Statistical analyses are summarized in Table S3.