The epidemics caused by the influenza virus are a serious threat to public health and the economy. Adding appropriate adjuvants to improve immunogenicity and finding effective mucosal vaccines to combat respiratory infection at the portal of virus entry are important strategies to boost protection. In this study, a novel type of core/shell protein nanoparticle consisting of influenza nucleoprotein (NP) as the core and NA1‐M2e or NA2‐M2e fusion proteins as the coating antigens by SDAD hetero‐bifunctional crosslinking is exploited. Immune‐stimulating complexes (ISCOMs)/monophosphoryl lipid A (MPLA) adjuvants further boost the NP/NA‐M2e SDAD protein nanoparticle‐induced immune responses when administered intramuscularly. The ISCOMs/MPLA‐adjuvanted protein nanoparticles are delivered through the intranasal route to validate the application as mucosal vaccines. ISCOMs/MPLA‐adjuvanted nanoparticles induce significantly strengthened antigen‐specific antibody responses, cytokine‐secreting splenocytes in the systemic compartment, and higher levels of antigen‐specific IgA and IgG in the local mucosa. Meanwhile, significantly expanded lung resident memory (RM) T and B cells (TRM/BRM) and alveolar macrophages population are observed in ISCOMs/MPLA‐adjuvanted nanoparticle‐immunized mice with a 100% survival rate after homogeneous and heterogeneous H3N2 viral challenges. Taken together, ISCOMs/MPLA‐adjuvanted protein nanoparticles could improve strong systemic and mucosal immune responses conferring protection in different immunization routes.
The effects of adjuvants for increasing the immunogenicity of influenza vaccines are well known. However, the effect of adjuvants on increasing the breadth of cross-reactivity is less well understood. In this study we have performed a systematic screen of different toll-like receptor (TLR) agonists, with and without a squalene-in-water emulsion on the immunogenicity of a recombinant trimerized hemagglutinin (HA) vaccine in mice after single-dose administration. Antibody (Ab) cross-reactivity for other variants within and outside the immunizing subtype (homosubtypic and heterosubtypic cross-reactivity, respectively) was assessed using a protein microarray approach. Most adjuvants induced broad IgG profiles, although the response to a combination of CpG, MPLA and AddaVax (termed ‘IVAX-1’) appeared more quickly and reached a greater magnitude than the other formulations tested. Antigen-specific plasma cell labeling experiments show the components of IVAX-1 are synergistic. This adjuvant preferentially stimulates CD4 T cells to produce Th1>Th2 type (IgG2c>IgG1) antibodies and cytokine responses. Moreover, IVAX-1 induces identical homo- and heterosubtypic IgG and IgA cross-reactivity profiles when administered intranasally. Consistent with these observations, a single-cell transcriptomics analysis demonstrated significant increases in expression of IgG1, IgG2b and IgG2c genes of B cells in H5/IVAX-1 immunized mice relative to naïve mice, as well as significant increases in expression of the IFNγ gene of both CD4 and CD8 T cells. These data support the use of adjuvants for enhancing the breath and durability of antibody responses of influenza virus vaccines.
more » « less- Award ID(s):
- 1763272
- NSF-PAR ID:
- 10367893
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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