Highly pathogenic avian influenza A/Guangdong/17SF003/2016 is immunogenic and induces cross-protection against antigenically divergent H7N9 viruses

Abstract

Avian influenza A(H7N9) epidemics have a fatality rate of approximately 40%. Previous studies reported that low pathogenic avian influenza (LPAI)-derived candidate vaccine viruses (CVVs) are poorly immunogenic. Here, we assess the immunogenicity and efficacy of a highly pathogenic avian influenza (HPAI) A/Guangdong/17SF003/2016 (GD/16)-extracted hemagglutinin (eHA) vaccine. GD/16 eHA induces robust H7-specific antibody responses in mice with a marked adjuvant antigen-sparing effect. Mice immunized with adjuvanted GD/16 eHA are protected from the lethal LPAI and HPAI H7N9 challenges, in stark contrast to low antibody titers and high mortality in mice receiving adjuvanted LPAI H7 eHAs. The protection correlates well with the magnitude of the H7-specific antibody response (IgG and microneutralization) or HA group 2 stem-specific IgG. Inclusion of adjuvanted GD/16 eHA in heterologous prime-boost improves the immunogenicity and protection of LPAI H7 HAs in mice. Our findings support the inclusion of GD/16-derived CVV in the pandemic preparedness vaccine stockpile.

A TLR9 agonist synergistically enhances protective immunity induced by an Alum-adjuvanted H7N9 inactivated whole-virion vaccine

“…Our results demonstrated that Alum/CpG 1018-adjuvanted WV vaccines may be more potent cross-protect against the Anhui strain than the Alum-adjuvanted WV vaccine. Consistent with a previous study [ 51 ], an AddaVax-adjuvanted H7 vaccine derived from A/Guangdong/17SF003/2016 provided cross-reactivity and protection against Anhui-like H7N9 challenge in mice. However, we found that neither the Alum/CpG 1018- nor the Alum-adjuvanted WV vaccines provided cross-protection against the recently emerged H7N9 A/Gansu/23277/2019 virus.…”

Functional and structural modifications of influenza antibodies during pregnancy

“…For titer and avidity determination, genes coding H3 HK HA, chimeric HA bearing H1 A/Puerto Rico/8/1934 stalk (group 1) with mismatched H16 HA head and chimeric HA bearing H3 HK stalk (group 2) with mismatched H4 HA head were synthesized as previously described (Stevens et al, 2004;Pica et al, 2012;Radvak et al, 2021)…”