Figure 1. A) Fractions of Sucrose Gradient showing different logs of HA titer. Seven fractions were collected from sucrose gradient followed by haemagglutination assay. As indicated, the highest titers were found for fractions 5 and 6 as highlighted in arrows. Dash line indicates the base line. B) Immunobloting of different fractions was performed to determine the presence of H1, H3, and M1 in VLPs as illustrated.