Comparing the antibody responses against recombinant hemagglutinin proteins of avian influenza A (H5N1) virus expressed in insect cells and bacteria

Shuo Shen, Geetha Mahadevappa, Hsueh Ling Janice Oh, Yu Wee Boon, Yook Wah Choi, Le Ann Hwang, Gee Lim Seng, Wanjin Hong, Sunil K. Lal, Yee Joo Tan

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34 Citations (Scopus)


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 microneutralization 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 antiserum 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.

Original languageEnglish
Pages (from-to)1972-1983
Number of pages12
JournalJournal of Medical Virology
Issue number11
Publication statusPublished - Nov 2008
Externally publishedYes


  • Baculovirus
  • HA5 pseudotyped lentiviral particles
  • Membrane fusion
  • Neutralizing antibodies

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