TABLE 1.

Antigens used for N2 antisera generation (reference antigen) and to test N2 antigenic relationships (contemporary and human antigens)

Antigen	Abbreviation	Subtype	N2 clade	Virus propagation	Accession no.
Reference antigens
A/swine/Texas/4199-2/1998	TX/98	H3N2	98B	MDCK	CY095677
A/swine/Minnesota/02011/2008	MN/08	H1N2	98A.1	MDCK	HM461804
A/swine/South Dakota/A01349341/2013	SD/13	H1N2	98A.2	MDCK	KC844211
A/swine/Oklahoma/A01409770/2014	OK/14	H1N2	98B.2	MDCK	KJ437590
A/turkey/Ohio/313053/2004	OH/04	H3N2	2002	MDCK	EU735820
A/swine/Nebraska/A01492366/2014	NE/14	H1N2	02A.1	MDCK	KJ549772
A/swine/New York/A01104005/2011	NY/11	H3N2	02A.2	MDCK	JN940424
A/swine/Minnesota/A01678475/2016	MN/16	H3N2	02B.1	MDCK	KY349114
A/swine/Iowa/A01480656/2014	IA/14	H3N2	02B.2	MDCK	KJ635930
Contemporary N2 antigens
A/swine/Illinois/A02216460/2017	IL/17	H1N2	1998A.2	MDCK	MF375250
A/swine/Indiana/A01894974/2016	IN/16	H1N2	1998B.1	MDCK	KX255806
A/swine/Iowa/A02217289/2017	IA/17	H1N2	1998B.2	MDCK	MF455500
A/swine/Iowa/A01778372/2016	IA/8372	H1N2	2002A.1	MDCK	KX772386
A/swine/Iowa/A01778106/2016	IA/8106	H3N2	2002A.2	MDCK	KX761361
A/swine/Illinois/A01671610/2016	IL/16	H1N2	2002B.2	MDCK	KY486460
A/swine/Oklahoma/A02157314/2018	OK/18	H1N2	2002B.1	MDCK-L	MH259506
A/swine/North Carolina/A02156991/2018	NC/18	H3N2	2002B.1	MDCK	MH201009
Human N2 antigens
A/Wuhan/359/1995	WU/95	H3N2		MDCK-L	CY112823
A/Sydney/5/1997	SY/97	H3N2		MDCK-L	AJ291403
A/Moscow/10/1999	MO/99	H3N2		MDCK-L	AJ458267
A/Fujian/411/2002	FU/02	H3N2		MDCK-L	CY088485
A/Wisconsin/67/2005	WI/05	H3N2		MDCK-L	CY034118
A/Brisbane/10/2007	BR/07	H3N2		Egg	CY035024
A/Perth/16/2009	PE/09	H3N2		Egg	CY081429
A/Victoria/361/2011	VI/11	H3N2		MDCK	KJ942681
A/Hong Kong/4801/2014	HK/14	H3N2		MDCK	EPI578429