Integrity of a recombinant hemagglutinin protein of an avian influenza virus

An open reading frame representing cDNA from a hemagglutinin (HA) encoding gene of a low pathogenic avian influenza virus (AIV) subtype H10N7 was cloned in the pNMT1-TOPO vector under the control of thiamine response promoter. This construct was designated as pNMT1-HA. The pNMT1-HA construct was transformed into Schizosaccharomyces pombe for expression of HA antigen. The correct expression of recombinant HA protein was confirmed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. The level of expression of recombinant HA protein was approximately 0.2% of total soluble protein. Purified yeast-derived recombinant HA protein showed hemagglutination activity. The 2-D and 3-D scanning images of recombinant HA protein were observed with an atomic force microscope (AFM). The structural integrity of the HA protein under AFM and hemagglutination activity provided support that the recombinant HA protein may be suitable for development of AIV subunit vaccine for mass administration to poultry.