Immunogenicity and effectiveness of a bivalent influenza A/H1N2 vaccine strain against seasonal human influenza A viruses in mice
Recent studies and reports have documented the ability of the co-circulatingseasonal influenzaA/H1N1 (ancestor: 2009 pandemic H1N1) and A/H3N2 to exchange their genetic segments, generating a novelH1N2strain in different geographical localities around the world with an ability to infect human. This raises concerns and triggers alarms to develop a multivalent vaccine that can protect against the documented H1- and H3-typehuman influenza A viruses(IAVs).
Results
Here, we generated a PR8-based vaccine strain that carries the HA gene segment from the contemporaryH1N1 viruswhile theNAgene segment was derived from a currently circulating influenza A/H3N2 strain. A recombinant PR8-basedH1N2vaccine strain (rgH1N2), engineered byreassortmentbetween influenza A/H1N1 and A/H3N2 to mimic the documented human influenza A/H1N2, was used for immunization to provokeimmunogenicityand cross-antigenicity against the H1- and H3-type human IAVs and was evaluated for itsimmunogenicityand effectiveness in mice. Following challenge infection of rgH1N2-vaccinated mice with contemporary influenza A/H1N1 and A/H3N2, results revealed that rgH1N2-vaccinated mice showed less viral shedding, more survival, and lessbody weight losscompared to control unvaccinated groups and vaccinated mice with rgH1N1 and rgH3N2.
Conclusions
This study highlights the applicability of the PR8-based H1N2 vaccine strain to protect against seasonal IAVs and emphasizes the role of bothsurfaceproteins, HA and NA, to stimulate protective andneutralizing antibodiesagainst circulating influenza A/H1N1 and A/H3N2 strains.