Table 1.

Effect of the amino acid mutations in the globular region on CHA5 vaccine immunogenicity

Antisera†	EC90 of HA pseudotyped virus *
	VN1194‡ (clade 1)§	ID05 (clade 2.1)	TK (clade 2.2)	E319-02 (clade 2.3.2)	FJ (clade 2.3.4)	AN (clade 2.3.4)
CHA5	252 ± 46	89 ± 59	400 ± 67	159 ± 32	63 ± 15	79 ± 18
CHA5 S157P	32 ± 9	100 ± 22	25 ± 8	32 ± 9	200 ± 38	173 ± 22
CHA5 V190I	178 ± 34	72 ± 41	429 ± 85	122 ± 21	59 ± 18	81 ± 23
CHA5 P197S	224 ± 41	63 ± 15	389 ± 62	171 ± 38	63 ± 15	79 ± 18
CHA5II	252 ± 46	800 ± 124	1,600 ± 217	800 ± 120	200 ± 90	224 ± 99

TK, A/turkey/Turkey/1/2005.

^*The geometric means of EC₉₀ neutralization titer from three independent experiments.

^†The DNA vaccine antigen was used to elicit antiserum.

^‡The HA of the virus was used to produce HA-pseudotyped virus.

^§The clade to which the virus belongs.