Table 3. Amino acid substitutions found on the HA protein of influenza B viruses.
| Subunit | Epitope (Residue location) | Vic-1 (n = 67) | Yam-2 (n = 53) | Yam-3 (n = 71) |
|---|---|---|---|---|
| HA1 | 120-loop (116–137) | H122Y (22) | N116K (64) | |
| T121A (10) | ||||
| V124A (2) | ||||
| 150-loop (141–150) | I146V (67) | |||
| 160-loop (162–167) | A169E (2) | |||
| 190-helix (194–202) | D197N (66) | D196N (53) | D196N (71) | |
| T199N (2) | S202N (6) | |||
| A202E (21) | ||||
| Surrounding region | V6A (2) | V6I (18) | V11A (2) | |
| G68S (2) | T75N (2) | V29A (7) | ||
| V90I (6) | V176I (2) | L172Q (30) | ||
| A154E (8) | Y178N (3) | S207P (3) | ||
| N171S (4) | G229D (3) | M251V (13) | ||
| V177I (5) | T234R (3) | K298E (64) | ||
| I180V (3) | E312K (64) | |||
| V190I (3) | ||||
| K209N (18) | ||||
| I267V (2) | ||||
| HA2 | N46D (6) | |||
Only amino acid substitutions shared by 2 viruses or more are reported in this table. Substitutions are compared with vaccine strains of respective clades (S4–S6 Tables). Amino acid substitutions are numbered according to respective vaccine strains (B/Brisbane/60/2008 for Vic-1, B/Massachusetts/02/2012 for Yam-2, B/Wisconsin/01/2010 for Yam-3). Bold and italic text indicate previously reported positively selected sites. The number of Malaysian influenza viruses having the substitution is indicated inside parenthesis.