Table 3.
Amino acid substitution of the HA ‘Loop’ epitope
| Victoria ‘tip’ | ||||||||
|---|---|---|---|---|---|---|---|---|
| 178 | 185 | |||||||
| Yamagata 88 | ˗ | D | N | ˗ | K | T | A | T |
| DSO 010147 2007 | ˗ | . | . | Y | . | N | . | . |
| Vacc0405N 05S B Jilin 20 2003 | ˗ | . | . | . | . | N | . | . |
| Vacc0506N B Jiangsu 10 2003 | ˗ | . | . | . | . | N | . | . |
| Vacc0809NS B Florida 4 2006 | ˗ | . | . | . | . | N | . | . |
| Vacc1213N B Wisconsin 01 2010 | ˗ | . | . | Y | . | N | . | . |
| Singapore 2010-2011 | ˗ | . | . | Y | . | N | . | . |
| B Singapore 04 1991 | ˗ | . | . | - | . | . | . | . |
| B Singapore 11 1994 | ˗ | . | . | N | . | . | . | . |
| B Singapore 22 1998 | ˗ | . | . | N | . | . | . | . |
| B Singapore 31 1998 | ˗ | . | . | N | . | . | . | . |
| B Singapore 35 1998 | ˗ | . | . | N | . | . | . | . |
| B Singapore 222 1979 | ˗ | . | ˗ | N | . | . | . | . |
| B Singapore 1964 | ˗ | N | K | N | . | . | . | R |
| Victoria 87 | N | D | N | N | K | T | A | T |
| DSO Victoria | . | . | . | . | . | . | . | . |
| DSO 050629 2005 | . | . | . | . | . | . | . | . |
| Vacc04S B Hong Kong 330 2001 | . | E | . | . | . | . | . | . |
| Vacc0608NS B Malaysia 2506 2004 | . | . | . | . | . | . | . | . |
| Vacc0912NS B Brisbane 60 2008 | . | . | K | . | . | . | . | . |
| Singapore 2010-2011 | . | . | K | . | . | . | . | . |
| Lee40 | ˗ | . | . | . | . | . | . | I |
The ‘Loop’ epitope of the HA protein is the main neutralising epitope of viruses belonging to the Yamagata lineage. Specimens listed under B Yamagata 16 88 belong to the Yamagata lineage while specimens listed under B Victoria 2 87 belong to the Victoria lineage. DSO Victoria: specimens sequenced in this study belonging to the Victoria lineage. Identical amino acids are marked by a dot (.) and deletions are denoted by a dash (−).