Table 3. Titres (PFU/ml) of inter-serotype or intra-serotype FMDV chimera viruses with positive charged residue substitutions in the VP1 or VP3 capsid proteins.

Plaque morphology on BHK-21 cells are indicated.

Virus mutants	Mutations in VP3	Mutations in VP1	Cell lines, plague morphology and virus titres
			BHK-21	Plaque morphology	CHO-K1	CHO-677a	CHO-745b	CHO-Lec2c
vNAMSAT2	-	-	1.26×106	L, M, clear	N	N	N	N
rvNAMVP3135K	E135K	-	2.51×108	L, M, clear	N	N	N	N
rvNAMVP3135K,175K	E135K, E175K	-	7.94×106	L, M, clear	N	N	N	N
vSAUSAT2	-	-	1.6×105	L, M, opaque	N	N	N	N
rvSAUVP3158K	E158K	-	1.26×105	M, S, opaque	1.8×103	N	N	1.4×103
rvSAUVP150L,55N	-	V50L-D55N	2.51×106	L, M, opaque	N	N	N	N
rvSAUVP1158K	-	T158K	6.31×106	L, M, clear	2.9×104	N	N	1.4×104
rvSAUVP183K	-	E83K	2.51×106	M, S, clear	4.0×106	N	N	1.6×106
rvSAUVP183K,85R	-	E83K, T85R	7.94×104	M, S, clear	1.4×104	N	N	1.2×103
rvSAUVP1110KRR	-	110KGG112-KRR	3.98×108	L, clear	4.7×108	N	N	5.5×105

^a CHO cell mutant, heparan sulphate deficient (HS^-) cell line.

^b CHO cell mutant, heparan sulphate deficient (HS^-) and chondroitin sulphate deficient (CS^-) cell line.

^c CHO cell mutant, sialic acid deficient (SA^-) cell line.

N indicates no growth.

L is for large plaques (6–8 mm in diameter), M for medium plaques (3–5 mm in diameter) and S for small plaques (1–2 mm in diameter).