Fig 6. Prime-boost vaccination strategy effectively induces anti-FMDV antibodies in cattle and blocks virus circulation post-challenge.

In experiment 3, calves in group 1 (panels A, D, G) were unvaccinated. Calves in group 2 (panels B, E, H) were vaccinated with rSFV-FMDV-P1-2A-mIRES-3C on PVD 0 (dotted vertical line, marked rSFV) and then with O1 Manisa empty capsid particles on PVD 14 (dotted vertical line, marked ECs). Calves in group 3 (panels C, F, I) were vaccinated with O1 Manisa empty capsid particles on PVD 0 (dotted vertical line, marked ECs) and then with rSFV-FMDV-P1-2A-mIRES-3C on PVD 14 (dotted vertical line, marked rSFV). All animals were challenged with FMDV (O UKG/34/2001) on PVD 28 (indicated by solid vertical line, marked FMDV). Body temperatures in each animal were monitored on a daily basis (panels A-C). Sera were collected from each calf on the indicated days and assayed in the serotype O blocking ELISA (panels D-F). Results are presented as ODP (%) with a cut-off value of 50% (indicated by horizontal line). The presence of FMDV RNA circulating in serum was assayed by RT-qPCR (panels G-I). The results are presented as copies of FMDV RNA/ml of serum as in Fig 5. A level of 10⁷ copies/ml is indicated by a horizontal line.