FIG 1.

Strategy for obtaining chimeric FMD viruses of seven serotypes and confirming all serotypes. (A) Schematic depiction of the chimeric viruses and their plaques. LF-BK cells were used for the plaque-forming assay for all recombinants except Om-SAT2-SAU, which did not form plaques in these cells. ZZR cells were used to grow the latter recombinant instead. UTR, untranslated region. (B) Genetic differentiation of the VP1 regions by individual-strain-specific RT-PCR. (C) Confirmation of the presence of the appropriate FMDV structural protein in the recombinants by using rapid diagnosis kits (lateral-flow assay) for seven serotypes. In LFA1, the lateral-flow assay was designed to detect all serotypes (Svanova Co. Ltd.). In LFA2, the lateral-flow assay was designed to detect four serotypes (PBM Co. Ltd.). C and T indicate the control and test lines, respectively (structural proteins). (D) Antigen ELISA of the recombinants using reference serotype antisera against O Manisa (O1 BFS 1860 for antigen), A 464, Asia1 CAM 9/80, C3 Resende, SAT1-BOT 1/68, SAT2-ZIM 5/81, and SAT3-ZIM 4/81. O.D, optical density.