TABLE 2.

HAI reaction patterns of H9N2 viruses with various antisera

Antigen preparation	Reciprocal antibody HAI titer of:
	WHO reference		H9 antiserum
	H1	H3	Chicken (G1 strain)	Chicken (G9 strain)	Rabbit
H9N2 A/Hong Kong/1073/99 (MDCK cell)	<40	<40	640	80	320
H9N2 A/quail/Hong Kong/G1/97 (allantoic fluid)	80	320	2,560	80	40
H9N2 A/quail/Hong Kong/G1/97 (MDCK cell)	<40	<40	640	<40	320
H9N2 A/chicken/Hong Kong/G9/97 (allantoic fluid)	<40	<40	160	640	640
H9N2 A/chicken/Hong Kong/G9/97 (MDCK cell)	<40	<40	160	320	320
H9N2 A/chicken/Hong Kong/AP2/99 (allantoic fluid)	<40	<40	320	1,280	1,280
H9N2 A/quail/AP22/99 (allantoic fluid)	80	320	1,280	40	80
H9N2 A/quail/AP22/99 (MDCK cell)	<40	<40	2,560	40	80
H9N2 A/quail/AP24/99 (allantoic fluid)	<40	<40	160	40	320
H9N2 A/chukar/AP28/99 (allantoic fluid)	<40	<40	80	80	<40
H1 control antigen (WHO reference)	1,280	<40	<40	<40	<40
H3 control antigen (WHO reference)	<40	640	<40	<40	160