Influenza vaccines that can be administered intranasally or by other needle-free delivery routes have potential advantages over injected formulations in terms of patient compliance, cost, and ease of global distribution. Supramolecular peptide nanofibers have been investigated previously as platforms for vaccines and immunotherapies and have been shown to raise immune responses in the absence of exogenous adjuvants and without measurable inflammation. However, at present it has not been tested whether the immunogenicity of these materials extends to the intranasal route. Here we investigated the extent to which self-assembled peptide nanofibers bearing an influenza peptide epitope elicit antigen-specific CD8 T cell responses when delivered intranasally, and we compared these responses with those elicited by subcutaneous immunization. Peptides containing an epitope from influenza acid polymerase (PA) and the Q11 self-assembly domain formed nanofibers that were avidly taken up by dendritic cells in lung-draining mediastinal lymph nodes after intranasal immunization. Intranasally delivered nanofibers generated greater antigen-specific CD8 T cell responses in the lung-draining lymph nodes than subcutaneous immunizations while retaining the non-inflammatory character of the materials observed in other delivery sites. The CD8 T cells elicited systemically were functional as assessed by their ability to produce IFN-γ ex vivo, lyse epitope-pulsed target cells in vivo, and diminish viral loads in infected mice. Compared to subcutaneously delivered nanofibers, intranasally delivered peptide nanofibers significantly increased the number of persisting antigen-specific tissue resident memory CD8 T cells in the lung, allowing for a more rapid response to infection at 6 weeks post-vaccination. These results indicate that intranasally delivered self-assembled peptide nanofibers are immunogenic when delivering CD8 epitopes without adjuvant or CD4 epitopes, are non-inflammatory, and promote more lung-resident memory CD8 T cells compared to subcutaneous immunization.
A supramolecular peptide vaccine system was designed in which epitope-bearing peptides self-assemble into elongated
nanofibers composed almost entirely of alpha-helical structure. The nanofibers were readily internalized by antigen presenting
cells and produced robust antibody, CD4+ T-cell, and CD8+ T-cell responses without supplemental adjuvants in mice. Epitopes
studied included a cancer B-cell epitope from the epidermal growth factor receptor class III variant (EGFRvIII), the universal
CD4+ T-cell epitope PADRE, and the model CD8+ T-cell epitope SIINFEKL, each of which could be incorporated into supramolecular
multi-epitope nanofibers in a modular fashion.
Biomaterials employed to raise therapeutic immune responses have become a complex and active field. Historically, vaccines have been developed primarily to fight infectious diseases, but recent years have seen the development of immunologically active biomaterials towards an expanding list of non-infectious diseases and conditions including inflammation, autoimmunity, wounds, cancer, and others. This review structures its discussion of these approaches around a progression from single-target strategies to those that engage increasingly complex and multifactorial immune responses. First the targeting of specific individual cytokines is discussed, both in terms of delivering the cytokines or blocking agents, and in terms of active immunotherapies that raise neutralizing immune responses against such single cytokine targets. Next, non-biological complex drugs such as randomized polyamino acid copolymers are discussed in terms of their ability to raise multiple different therapeutic immune responses, particularly in the context of autoimmunity. Last, biologically derived matrices and materials are discussed in terms of their ability to raise complex immune responses in the context of tissue repair. Collectively, these examples reflect the tremendous diversity of existing approaches and the breadth of opportunities that remain for generating therapeutic immune responses using biomaterials.
to flow cytometry, cells were stained with DAPI to detect live and dead populations. Flow cytometry was preformed using a BD Canto FACS instrument and signals were compensated using single color controls. Counts of antigen specific T cells were taken by gating SIINFEKL specific T cells (CD4 − CD8 + B220 − F4/80 − Tetramer +) and multiplying the percentage of the total population by the total cell count after harvesting lymph nodes. here were performed under Duke University Institutional Animal Care and Use Committee protocol A264-18-11. Conflict of Interest J.H.C. and Y.W. are inventors on United States and PCT patent applications describing the Coil29 system.
The current paradigm that subunit vaccines require adjuvants to optimally activate innate immunity implies that increased vaccine reactogenicity will invariably be linked to improved immunogenicity. Countering this paradigm, nanoparticulate vaccines have been reported to act as delivery systems for vaccine antigens and induce immunity without the need for exogenous adjuvants or local inflammation; however, the mechanisms underlying the immunogenicity of nanoparticle vaccines are incompletely identified. Here, we show that antigens displayed on self-assembling nanofiber scaffolds and delivered intranasally are presented by CD103+ and CD11b+ lung dendritic cells that up-regulate CD80 and migrate into the draining lymph node (LN). This was accompanied by a nearly exclusive priming and accumulation of antigen-specific TH17 cells occurring independently in both LN and lung. Thus, self-assembling peptide nanofiber vaccines may represent a novel, needle- and adjuvant-free means of eliciting protective immunity against fungal and bacterial infections at skin and mucosal barrier surfaces.
Effective sublingual peptide immunization
requires overcoming challenges
of both delivery and immunogenicity. Mucosal adjuvants, such as cyclic-dinucleotides
(CDN), can promote sublingual immune responses but must be codelivered
with the antigen to the epithelium for maximum effect. We designed
peptide–polymer nanofibers (PEG-Q11) displaying nona-arginine
(R9) at a high density to promote complexation with CDNs via bidentate hydrogen-bonding with arginine side chains. We coassembled
PEG-Q11 and PEG-Q11R9 peptides to titrate the concentration of R9
within nanofibers. In vitro, PEG-Q11R9 fibers and
cyclic-di-GMP or cyclic-di-AMP adjuvants had a synergistic effect
on enhancing dendritic cell activation that was STING-dependent and
increased monotonically with increasing R9 concentration. The polyvalent
display of R9 on assembled nanofibers was significantly more effective
at promoting CDN-mediated DC activation in vitro than
mixing nanofibers with an equimolar concentration of unassembled R9
peptide. The sublingual administration of nanofibers revealed a bell-shaped
trend between increasing R9 concentration and enhancements to antigen
trafficking and the activation of DCs in the draining lymph nodes.
Intermediate levels of R9 within sublingually administered PEG-Q11
fibers were optimal for immunization, suggesting a balance between
polyarginine’s ability to sequester CDNs along the nanofiber
and its potentially detrimental mucoadhesive interactions. These findings
present a potentially generalizable biomaterial strategy for enhancing
the potency of CDN adjuvants and reveal important design considerations
for the nascent field of sublingual biomaterial immunization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.