Polyacrylamide gels run under reducing and nonreducing conditions for trimeric HA and HA1 and HA2 subunits bound and separate.

<p>Coomassie blue stain was used for protein and western blots with polyclonal antisera for protein identity. Gels are for vaccines (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0050830#pone-0050830-g004" target="_blank">Figure 4A</a>) and viruses (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0050830#pone-0050830-g004" target="_blank">Figure 4B</a>). Baculovirus expressed H3 HA was used as control (not shown).</p>