title: Comparing the antibody responses against recombinant hemagglutinin proteins of avian influenza A (H5N1) virus expressed in insect cells and bacteria.
abstract: The hemagglutinin (HA) of influenza A virus plays an essential role in mediating the entry of the virus into host cells. Here, recombinant full-length HA5 protein from a H5N1 isolate (A/chicken/hatay/2004(H5N1)) was expressed and purified from the baculovirus-insect cell system. As expected, full-length HA5 elicits strong neutralizing antibodies, as evaluated in micro-neutralization tests using HA5 pseudotyped lentiviral particles. In addition, two fragments of HA5 were expressed in bacteria and the N-terminal fragment, covering the ectodomain before the HA1/HA2 polybasic cleavage site, was found to elicit neutralizing antibodies. But the C-terminal fragment, which covers the remaining portion of the ectodomain, did not. Neutralizing titer of the anti-serum against the N-terminal fragment is only four times lower than the anti-serum against the full-length HA5 protein. Using a novel membrane fusion assay, the abilities of these antibodies to block membrane fusion were found to correlate well with the neutralization activities.
authors.affiliation: Collaborative Anti-viral Research Group, Institute of Molecular and Cell Biology, Singapore, Singapore.
authors.forename: Shuo
authors.initials: S
authors.lastname: Shen
authors.forename: Geetha
authors.initials: G
authors.lastname: Mahadevappa
authors.forename: Hsueh-Ling Janice
authors.initials: HL
authors.lastname: Oh
authors.forename: Boon Yu
authors.initials: BY
authors.lastname: Wee
authors.forename: Yook-Wah
authors.initials: YW
authors.lastname: Choi
authors.forename: Le-Ann
authors.initials: LA
authors.lastname: Hwang
authors.forename: Seng Gee
authors.initials: SG
authors.lastname: Lim
authors.forename: Wanjin
authors.initials: W
authors.lastname: Hong
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Lal
authors.forename: Yee-Joo
authors.initials: YJ
authors.lastname: Tan
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D001419:Bacteria; D016367:Baculoviridae / Q000235:genetics; D002460:Cell Line; D005822:Genetic Vectors; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology*; D053124:Influenza A Virus, H5N1 Subtype / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology*; D018411:Spodoptera
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D011994:Recombinant Proteins; C109963:hemagglutinin, avian influenza A virus