TABLE 2.

Antigenic analysis of H5N1 influenza viruses from Hong Kong by the HI assay

Virus	Polyclonal antisera HI titers to:					Monoclonal antibody HI titers to:
	Anti-A/HK/156 (483)/97 (sheep)	Anti-A/Gs/HK/ 437-4/99 (chicken)	Anti-A/Tern/ SA/61 (goat)	Anti-A/Ck/HK/ YU22/02 (chicken)	Anti-A/Gs/ HK/739.2/02 (duck)	A/Ck/PA/1370/83				A/Ck/PA/8125/83
						CP24	CP25	CP46	CP58	176/26	406/07
HK/156/97	1,280b	5,120	10,240	1,280	320	1,600	3,200	6,400	6,400	12,800	12,800
Ck/HK/258/97	1,280	2,560	160	160	—a	1,600	1,600	—a	6,400	12,800	400
Ck/HK/FY150/01	320	1,280	40	160	—	400	400	1,600	6,400	6,400	3,200
Ph/HK/FY155/01	160	1,280	—	80	—	800	800	800	6,400	3,200	1,600
Ck/HK/822.2/01	1,280	2,560	—	160	—	1,600	200	—	6,400	200	—
Ck/HK/YU562/01	320	1,280	—	160	—	800	800	800	1,600	100	100
Ck/HK/873.3/01	160	1,280	—	160	—	1,600	800	200	800	800	—
Ck/HK/31.4/02	640	1,280	—	160	—	100	100	—	200	100	—
Ck/HK/YU22/02	—	1,280	—	320	—	100	100	—	—	100	—
Ck/HK/86.3/02	40	2,560	160	640	80	—	—	—	—	100	—
Teal/HK/2978.1/02	320	160	40	80	—	800	400	400	800	100	—
RB poch/HK/821/02	—	320	—	40	40	—	—	—	—	—	—
Gs/HK/739.3/02	—	640	—	160	40	100	—	—	—	—	—
Gs/HK/739.2/02	—	1,280	—	320	80	400	—	—	—	—	—
Reference strains
Tern/SA/61	40	1,280	160	40	—	—	—	1,600	200	800	—
Ck/PA/1370/83	NDc	ND	ND	ND	ND	12,800	12,800	6,400	3,200	6,400	6,400
Gs/HK/437-4/99	ND	5,120	ND	ND	ND	ND	ND	ND	ND	ND	ND

^a— titer, <1:40 for antisera and <1:100 for monoclonal antibodies.

^bUnderlined values are titers of homologous virus.

^cND, not determined.