Expression and detection of hemagglutinin gene of H7N9 avian influenza virus in baculovirus

Abstract

Objective Baculovirus expression system was used to express the hemagglutinin (HA) protein of H7N9 avian influenza virus and to obtain the protein, so as to verify its activity. Methods Full length HA gene of H7N9 avian influenza was synthesized, the gene was then amplified and cloned into a pFastBacI vector. A recombinant baculovirus expression vector containing the target gene was then constructed by homologous recombination. After identification by PCR, the vector was transfected into Sf9 insect cells. The expression of recombinant HA protein was detected by SDS-PAGE and western blotting. HA protein was purified, and its erythrocyte agglutination activity was identified by hemagglutination test. Results PCR results showed that the size of the amplified product of the recombinant baculovirus expression vector was about 4000 bp. The molecular mass of the purified protein calculated by SDS-PAGE was 63KD. Western blot assay indicated that the expressed protein can react specifically with antibody against HA and the band was in consistent with prediction. The results of hemagglutination test showed that the expressed protein can agglutinate red blood cells, the agglutination activity was 1: 64. Conclusions The HA protein of H7N9 avian influenza virus was correctly expressed in recombinant baculovirus and the expressed protein had hemagglutination activity. Key words: Avian influenza; Virus; Gene expression; HA protein; Baculovirus expression system