Adsorption of neutralization activity using HA peptides.

HA [(-10)-223] can adsorb most of the neutralizing activity in polyclonal sera. Sera from sheep hyperimmunized with bromelain-treated rgA/Vietnam/1203/2004 (FDA), or from ferrets infected with wild-type A/Vietnam/1203/2004 virus (CDC) were adsorbed on different H5 HA peptides and subjected to a microneutralization assay performed with rgA/Vietnam/1203/2004 virus. End-point neutralization titers of various pre- or postadsorbed sera are shown.