Table 3. Nucleotide and amino acid similarities of the S1 protein genes^a among the five Chinese IBV isolates and other IBV strains.

Strain	LD3	LS2	LX4	LH2	LHI10	Q1	T3	J2	A1211	A1171	M41	H120	H52	UK/7/93	D274	B1648	KB8523	Beau	Conn	Ark99	GA/98
	Amino acid identity (%)
LD3		92	94	98	98	75	76	76	77	77	74	75	74	76	76	76	75	74	73	75	53
LS2	95		93	92	92	76	76	76	78	77	75	76	75	76	75	76	75	75	74	74	53
LX4	96	96		94	94	75	76	76	78	78	75	75	75	77	75	76	75	75	73	75	52
LH2	99	95	96		98	76	76	76	77	77	74	75	75	76	76	76	75	75	73	75	53
LHI10	99	95	96	99		76	76	76	78	77	75	75	74	76	76	76	75	75	72	75	53
Q1	76	76	76	76	76		98	99	77	77	74	74	73	75	80	76	74	73	73	76	53
T3	76	76	76	76	76	99		99	78	78	74	74	74	74	80	76	74	73	73	77	52
J2	76	76	76	76	76	99	99		77	78	82	82	82	75	80	76	75	73	73	77	52
A1211	78	78	79	78	78	77	77	77		92	82	82	82	77	77	75	82	82	79	78	53
A1171	78	78	79	78	78	77	77	77	95		82	82	82	76	77	75	81	81	79	78	53
M41	76	77	77	77	77	77	77	77	81	81		95	96	74	77	74	95	97	88	75	53
H120	76	77	77	77	77	76	76	76	81	81	97		99	74	78	74	99	96	94	76	53
H52	76	77	77	77	77	76	76	76	81	81	97	99		74	78	74	98	95	94	76	52
UK/7/93	78	78	79	78	78	78	78	78	77	77	78	78	78		78	78	75	74	73	76	48
D274	77	77	77	77	77	80	80	80	78	78	80	80	81	78		78	78	78	76	78	53
B1648	77	77	77	77	77	78	78	78	75	76	77	77	77	79	78		75	75	73	78	52
KB8523	76	77	77	77	77	76	76	76	81	81	97	99	99	78	81	77		95	87	76	53
Beau	76	77	77	76	76	76	76	76	81	81	98	97	97	78	81	78	97		86	76	53
Conn	74	74	74	74	73	74	74	74	78	78	91	91	90	75	76	74	90	90		73	51
Ark99	75	75	76	75	75	76	76	76	77	78	78	78	77	77	78	78	78	78	75		51
GA/98	60	60	60	60	60	61	61	61	61	62	62	62	62	60	61	61	62	62	61	61
	Nucleotide identity (%)

Top right, amino acid identity (%); bottom left, nucleotide identity (%).

^aThe first 1605 nucleotides, starting at the AUG translation start codon, of the S1 protein genes were compared.