Comparing the antibody responses against recombinant hemagglutinin proteins of avian influenza A (H5N1) virus expressed in insect cells and bacteria.
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.
Shen
Shuo
S
Collaborative Anti-viral Research Group, Institute of Molecular and Cell Biology, Singapore, Singapore.
Mahadevappa
Geetha
G
Oh
Hsueh-Ling Janice
HL
Wee
Boon Yu
BY
Choi
Yook-Wah
YW
Hwang
Le-Ann
LA
Lim
Seng Gee
SG
Hong
Wanjin
W
Lal
Sunil K
SK
Tan
Yee-Joo
YJ
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
D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines; D011994:Recombinant Proteins; C109963:hemagglutinin, avian influenza A virus