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Abstract 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.
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Modulating antigen processing through metal–organic frameworks to bias adaptive immunity
Vaccines induce specific immunity through antigen uptake and processing. However, while nanoparticle vaccines have elevated uptake, the impact of intracellular protein release and how this affects processing and downstream responses are not fully understood. Herein, we reveal how tuning unmodified antigen release rate, specifically through modulation of metal–organic framework (MOF) pore size, influences the type and extent of raised adaptive immunity. We use two MOFs in the NU-100x series with 1.4 nm difference in pore diameter, employ facile postsynthesis loading to achieve significant internalization of model protein antigen ovalbumin (ca.1.4 mg/mg), and observe distinct antigen release and intracellular processing profiles influenced by MOF pore size. We investigate how this difference in release biases downstream CD8+, TH1, and TH2 T cell responses. Ovalbumin-loaded NU-1003 induced 1.8-fold higher CD8+:CD4+T cell proliferation ratio and displayed 2.2-fold greater ratio of CD4+TH1:TH2 cytokines compared to ovalbumin-loaded NU-1000. Antigen released from NU-1000 in vivo exhibited stronger antigen-specific IgG responses, which is dependent on CD4+T cells (up to ninefold stronger long-term antibody production and 5.9-fold higher IgG1:IgG2a ratio), compared to NU-1003. When translated to wild-type SARS-CoV-2 receptor-binding domain (RBD) protein, RBD-loaded NU-1000 induced 60.5-fold higher IgG1:IgG2a compared to NU-1003. Wild-type RBD-loaded NU-1000 immunization also induced a greater breadth of epitope recognition compared to NU-1003, as evidenced by increased binding antibodies to the Omicron RBD variant. Overall, this work highlights how antigen release significantly influences immunity induced by vaccines and offers a path to employ unmodified antigen release kinetics to drive personalized protective responses.
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- PAR ID:
- 10645838
- Publisher / Repository:
- Proceedings of the National Academy of Sciences
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 122
- Issue:
- 45
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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