TABLE 1.

Characteristics of A₂₄-B9 FMDV in cell culture

A24Cru-B9 virus passage history	Amino acid sequence at GH loop of VP1a	Plaque phenotype in BHK-21 cell monolayers	Virus titer (PFU/ml)
No passages	RSGDMESLAARVVK	Turbid	9.0 × 105
6× BHK3-αvβ6	--------------	Turbid	2.5 × 105
4× BHK21	-R------------	Clear	5.0 × 107
6× BHK3-αvβ6, 4× BHK21	-R-------A----	Clear	1.0 × 107
3× FBK	-----K--------	Turbid	4.4 × 105
3× FBK, 4× BHK21	-R---K--------	Clear	1.2 × 107

^aThe A₂₄-B9 virus amino acid residues 143 to 156 in VP1, with the SGD triplet in boldface letters, is displayed. The dashes represent conserved residues, and the emergent mutations from the original virus are indicated.