Fig. 4

Molecular analysis of HA1 amino acid sequences of the isolates and reference strains. Potential glycosylation sites were marked with red box. Previously defined antigenic sites were indicated: Site Sa (green box), site Sb (purple box), site Ca1 (black shade), site Ca2 (blue box), Cb (orange box). The pentagram represents the receptor-binding sites. A/HongKong/1290/1993(H1N1) and A/swine/Hong Kong/NS1022/2001(H1N1) are all from the classical swine lineage. A/California/04/2009(H1N1) and A/Mexico/4486/2009(H1N1) are from the pandemic H1N1/2009 sublineage of classical swine lineage. A/HongKong/294/2009(H1N2) is from the triple reassortant sublineage of classical swine lineage. A/Alaska/1935(H1N1), A/New Jersey/1976(H1N1), A/Hong Kong/117/1977(H1N1) and A/Victoria/36/1988(H1N1) are all from the human lineage. A/swine/Hong Kong/NS184/2009(H1N1) is from the avian lineage