FIG. 3.

Alignment of HA1 amino acid sequences of SW98 viruses with that of A/Finland/339/95 (H3N2). The residues in open boxes are potential glycosylation sites; shaded residues denote the receptor-binding site; residues in reverse type represent amino acid changes that may have been derived from a human virus precursor (see text); underlined residues are antigenic sites (lowercase letters indicate discrete antigenic sites).