TABLE 2.

A/CA/7/09 HA variants identified from MDCK cells and introduced by reverse genetics

VirusAmino acid at indicated positiona (H3 position)Virus titerb in eggs (log10 FFU/ml ± SE)
119 (122)153 (156)154 (157)155 (158)186 (189)222 (225)223 (226)278 (280)
V5KKKGAGQT7.4 ± 0.14
V6DR7.7 ± 0.14
V5-119NN8.3 ± 0.06
V5-119EE8.3 ± 0.07
V5-153EE8.3 ± 0.05
V5-154EE8.6 ± 0.05
V6-186DDDR8.4 ± 0.06
V5-186DD8.3 ± 0.15
V5-119E/186DED8.5 ± 0.06
V6-119NNDR7.9 ± 0.20
V6-119N/186DNDDR8.1 ± 0.09
V5-155EE8.4 ± 0.11
V5-278KK7.6 ± 0.19
V6-155EEDR8.4 ± 0.19
V6-278KDRK7.7 ± 0.27
  • a Amino acid changes from V5 or V6 are shown.

  • b Virus titers are mean titers from at least three virus stocks.