Fig. 6. Decreased viremia and high levels of E2-specific antibodies were detected in pigs challenged with classical swine fever virus (CSFV) at 2 months and 4 months post-vaccination. CSFV RNA was detected in the serum (A) and nasal cavity (B) by real-time reverse transcriptase polymerase chain reaction analyses in which threshold cycle values equal to or less than 40 were considered CSFV positive. Both 2 months and 4 months post-vaccination KNB E2-vaccinated pig groups exhibited decreased viremia and produced a significantly higher level of E2-specific antibodies post-CSFV challenge (dilution 1/10,000) (C) compared with the level in the phosphate-buffered saline–vaccinated CSFV-challenged (−/+) control group. Data are presented as mean ± SEM values for five pigs per group. ^*p < 0.05.