TABLE 3.

Comparison of amino acid sequences of the original viruses and their MB variants^a

Virus (genotype)	PB2 sequence at amino acid:					PA sequence at amino acid:
	305	307	463	627	738	10	97	212	317	331	343	349	357	361	364	373	395	501	519	528	542
HK/483/97	E	A	I	K	K	N	T	R	W	N	A	E	T	K	S	N	S	Y	N	T	V
HK/486/97	E	A	I	E	K	N	T	R	W	N	A	E	T	K	S	N	S	Y	N	T	V
Ck/HK/YU822.2/01 (A)	E	A	I	E	K	N	T	R	W	N	A	Q	T	R	S	K	S	Y	N	T	I
Ck/HK/YU822.2/01-MB (A)	E	A	I	E	N	I	T	P	W	N	A	E	T	K	G	N	S	Y	N	T	V
Ck/HK/YU562/01 (B)b	E	A	I	E	K	N	T	R	W	N	A	E	T	K	G	N	S	Y	N	T	V
Ph/HK/FY155/01 (C)	E	A	V	E	K	N	T	R	W	N	T	E	T	K	G	N	G	Y	N	T	V
Ph/HK/FY155/01-MB (C)	S	G	I	K	K	N	T	R	W	N	A	E	T	K	G	N	G	F	N	T	V
Ck/HK/FY150/01 (D)	E	A	I	E	K	N	T	R	W	N	A	E	T	K	G	N	S	Y	S	T	V
Ck/HK/FY150/01-MB (D)	E	A	I	E	K	N	I	R	W	N	A	E	T	K	G	N	G	Y	N	T	V
Ck/HK/NT873.3/01 (E)	E	A	I	E	K	N	T	R	C	T	A	E	A	K	G	N	S	Y	N	S	V
Ck/HK/NT873.3/01-MB (E)	E	A	I	E	K	N	T	R	W	N	A	E	T	K	G	N	S	Y	N	T	V

^aPositions of amino acid differences observed among the original viruses and their MB variants were compared to those in phenotypes of human H5N1/97 isolates with high and low pathogenicity in mice (13) and with those in virus of genotype B, which did not infect mouse brain. HK/483/97 and HK/486/97 are phenotypes of Hong Kong 1997 viruses (13) of high and low pathogenicity, respectively, in mice. Amino acids in boldface indicate amino acid changes between original isolates and MB variants.

^bVirus of genotype B not isolated from mouse brain.