Lin, YujuYujuLinDeng, MingchungMingchungDengWu, S. H.S. H.WuChen, Y. L.Y. L.ChenCheng, H. C.H. C.ChengCHIA-YI CHANGLee, Min ShiuhMin ShiuhLeeChien, Maw ShengMaw ShengChienHuang, ChinchengChinchengHuang2022-11-112022-11-11200809167250https://www.scopus.com/inward/record.uri?eid=2-s2.0-57349086076&doi=10.1292%2fjvms.70.1147&partnerID=40&md5=e6193aaedb24ea0cdf17243d88bfbc88https://scholars.lib.ntu.edu.tw/handle/123456789/624624Since outbreaks of highly pathogenic avian influenza (HPAI) in both human and poultry from 2003, it is critical to have effective vaccines. A cDNA fragment coding the entire hemagglutinin (HA) gene derived from an H5N1 strain (A/duck/China/E319-2/03) was cloned and expressed using the baculovirus system. Two weeks after receiving two doses of recombinant HA (rHA) vaccines, chickens develop high antibody response for hemagglutination inhibition (HI) at titer 7.2 log2. Challenge studies revealed that vaccinated chickens with HI titers greater than 3 log2 could have immunoprotection against the same HPAI H5N1 strain virus challenge through intranasal route. Additionally, HI titer of 5 log2 determined whether the live viruses could not be detected from oropharyngeal, cloacal discharge or in tissues. This result suggests that the rHA expressed from baculovirus system could be a candidate for the development of a safe and efficient subunit vaccine for HPAI (H5N1).Baculovirus expression system; H5N1; Hemagglutination inhibition; Highly pathogenic avian influenza (HPAI); Subunit vaccine[SDGs]SDG3influenza vaccine; recombinant protein; virus hemagglutinin; animal; article; avian influenza; chicken; duck; genetics; immunology; Influenza virus A H9N2; isolation and purification; molecular cloning; virology; virus shedding; Animals; Chickens; Cloning, Molecular; Ducks; Hemagglutinins, Viral; Influenza A Virus, H9N2 Subtype; Influenza in Birds; Influenza Vaccines; Recombinant Proteins; Virus Shedding; Aves; Gallus gallusjournal article10.1292/jvms.70.1147190571302-s2.0-57349086076