Journal of virology
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Journal of virology · Oct 2010
Recombinant soluble, multimeric HA and NA exhibit distinctive types of protection against pandemic swine-origin 2009 A(H1N1) influenza virus infection in ferrets.
The emergence and subsequent swift and global spread of the swine-origin influenza virus A(H1N1) in 2009 once again emphasizes the strong need for effective vaccines that can be developed rapidly and applied safely. With this aim, we produced soluble, multimeric forms of the 2009 A(H1N1) HA (sHA(3)) and NA (sNA(4)) surface glycoproteins using a virus-free mammalian expression system and evaluated their efficacy as vaccines in ferrets. Immunization twice with 3.75-microg doses of these antigens elicited strong antibody responses, which were adjuvant dependent. ⋯ Our observations demonstrate the great vaccine potential of multimeric HA and NA ectodomains, as these can be easily, rapidly, flexibly, and safely produced in high quantities. In particular, our study underscores the underrated importance of NA in influenza vaccination, which we found to profoundly and specifically contribute to protection by HA. Its inclusion in a vaccine is likely to reduce the HA dose required and to broaden the protective immunity.