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Emerging evidence suggests seeding and prion-like propagation of mutant Superoxide Dismutase 1 (SOD1) misfolding to be a potential mechanism for ALS pathogenesis and progression. Immuno-targeting of misfolded SOD1 has shown positive clinical outcomes in mutant SOD1 transgenic mice. However, a major challenge in developing active immunotherapies for proteinopathies such as ALS is the design of immunogens enabling exclusive recognition of pathogenic species of a self-protein. Ideally, one would achieve a robust antibody response against the disease-misfolded protein while sparing the natively folded conformer to avoid inducing deleterious autoimmune complications, or inhibiting its normal function. Using a motor neuron disease mouse model expressing human SOD1-G37R, we herein report the immunogenicity and therapeutic efficacy of two ALS vaccines, tgG-DSE2lim and tgG-DSE5b, based on the notion that native SOD1 would undergo early unfolding in disease to present "disease specific epitopes" (DSE). Both vaccines elicited rapid, robust, and well-sustained epitope-specific antibody responses with a desirable Th2-biased immune response. Both vaccines significantly extended the life expectancy of hSOD1 G37R mice, with tgG-DSE2lim displaying greater protection than tgG-DSE5b at earlier pre-symptomatic stage. tgG-DSE5b, but not tgG-DSE2lim, significantly delayed disease onset and appreciably slowed disease progression. This implies that conformationally distinct species of misfolded SOD1 may derive from the same mutation, thereby modifying disease phenotypes in a different fashion. Our results validate the rationale for conformation-based immuno-targeting of misfolded SOD1 as a promising therapeutic strategy to slow or even halt disease progression in familial ALS associated with SOD1 mutations, as well as a prophylactic intervention for carriers of SOD1 mutations. Our study not only provides important proof-of-principle data for the development of a safe and effective human therapeutic/prophylactic ALS vaccine against misfolded SOD1, but also predicts a great potential to extend our DSE-based vaccination approach to other types of ALS, such as those associated with TDP-43 proteinopathies., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Chronic wasting disease (CWD) is a fatal prion disease affecting multiple cervid species. Effective management tools for this disease, particularly in free-ranging populations, are currently limited. We evaluated a novel CWD vaccine in elk (Cervus canadensis) naturally exposed to CWD through a prion-contaminated environment. The vaccine targets a YYR disease-specific epitope to induce antibody responses specific to the misfolded (PrP Sc ) conformation. Female elk calves (n = 41) were captured from western Wyoming and transported to the Thorne-Williams Wildlife Research Center where CWD has been documented since 1979. Elk were held in contaminated pens for 14 to 20 days before being alternately assigned to either a vaccine (n = 21) or control group (n = 20). Vaccinated animals initially received two vaccinations approximately 42 days apart and annual vaccinations thereafter. Vaccination induced elevated YYR-specific antibody titers in all animals. Elk were genotyped for the prion protein gene at codon 132, monitored for clinical signs of CWD through daily observation, for disease status through periodic biopsy of rrectoanal mucosa-associated lympoid tissue (RAMALT), and monitored for YYR-specific serum antibody titres. Mean survival of vaccinated elk with the 132MM genotype (n = 15) was significantly shorter (800 days) than unvaccinated elk (n = 13) of the same genotype (1062 days; p = 0.003). Mean days until positive RAMALT biopsy for 132MM vaccinated elk (6 7 8) were significantly shorter than unvaccinated 132MM elk (990; p = 0.012). There was, however, no significant difference in survival between vaccinated (n = 4) and control (n = 5) elk with the 132ML genotype (p = 0.35) or in timing of positive RAMALT biopsies of 132ML elk (p = 0.66). There was no strong (p = 0.17) correlation between YYR-specific antibody titers and survival time. Determining the mechanism by which this vaccine accelerates onset of CWD will be important to direct further CWD vaccine research., (Published by Elsevier Ltd.)

Bacteriophage are structurally stable in the gastro-intestinal tract and have favorable traits of safety, stability, ease of production, and immunogenicity. These attributes make them potential candidates as oral vaccine delivery vehicles but little is known about their capacity to induce mucosal immune responses in the small intestine. Whole body imaging of mice confirmed lambda bacteriophage (LP) were distributed throughout the gastro-intestinal tract 24 h after oral delivery. In newborn calves, targeted delivery of LP within the small intestine confirmed LP were immunogenic in a dose-dependent manner and were taken up by Peyer's patches. LP-specific IgA responses were induced within both Peyer's patches and draining mesenteric lymph nodes. A lambda display phage (LDP) was constructed to present three immunogenic disease specific epitopes (DSE) from cervid prion protein (amino acids 130-140 [YML]; 163-170 [YRR]; and 171-178[YRR]) fused to phage capsid head protein D (LDP-DSE). Targeted delivery of purified LDP-DSE to intestinal segments induced IgA responses to all three peptide epitopes. Further, delivery of bacteria expressing soluble D-DSE also induced epitope-specific IgA responses in the targeted Peyer's patches. These are the first studies to report use of LDP to induce epitope-specific IgA responses in the small intestine andconfirm Peyer's patchesfunction as a site for LP uptake. Furthermore, IgA responses to peptide epitopes on LDP were observed in the absence of a mucosal adjuvant. These observations confirm LDP have the capacity to function as a mucosal delivery vehicle with protein D as an effective carrier for peptide epitopes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Prion diseases represent a novel form of infectivity caused by the propagated misfolding of a self-protein (PrP(C)) into a pathological, infectious conformation (PrP(Sc)). Efforts to develop a prion vaccine have been complicated by challenges and potential dangers associated with induction of strong immune responses to a self protein. There is considerable value in the development of vaccines that are specifically targeted to the misfolded conformation. Conformation specific immunotherapy depends on identification and optimization of disease-specific epitopes (DSEs)(1) that are uniquely exposed upon misfolding. Previously, we reported development of a PrP(Sc)-specific vaccine through empirical expansions of a YYR DSE. Here we describe optimization of two additional prion DSEs, YML of β-sheet 1 and a rigid loop (RL) linking β-sheet 2 to α-helix 2, through in silico predictions of B cell epitopes and further translation of these epitopes into PrP(Sc)-specific vaccines. The optimized YML and RL vaccines retain their properties of immunogenicity, specificity and safety when delivered individually or in a multivalent format. This investigation supports the utility of combining DSE prediction models with algorithms to infer logical peptide expansions to optimize immunogenicity. Incorporation of optimized DSEs into established vaccine formulation and delivery strategies enables rapid development of peptide-based vaccines for protein misfolding diseases., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Host defence peptides (HDPs) have a variety of potential therapeutic applications, including as vaccine adjuvants, energizing efforts for modification strategies to address their toxicity and instability. Here we compare l, d and RI-Bac2A as vaccine adjuvants. d and RI-Bac2A are equally resistant to proteolytic degradation with no increases in toxicity, however, only RI-Bac2A maintains adjuvant activity of the natural peptide through conserved induction of a Th2 immune response. As HDPs potentiate the adjuvant activity of CpG ODNs, the isomers were also evaluated as co-adjuvants. l-Bac2A has no significant co-adjuvant activity while CpG/RI-Bac2A induces antibody titres significantly higher than CpG (P<0.01), CpG/l-Bac2A (P<0.01) or CpG/d-Bac2A (P<0.01). None of the isomers influence ODN duration or distribution but l and RI-Bac2A promote ODN uptake into B cells and antigen presenting cells. The enhanced adjuvant and co-adjuvant of RI-Bac2A is hypothesized to result from an undefined combination of increased stability and retained biological activity supporting application of retro-inversion to this, and potentially other HDPs., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Transmissible spongiform encephalopathies (TSEs) depend on misfolding of a normal cellular protein (PrP(C)) to an infectious conformation (PrP(Sc)). Targeting PrP(Sc) may represent an effective strategy for immunotherapy while avoiding consequences associated with immune responses to self-proteins. A weakly immunogenic epitope of PrP(C) (YYR), which induces PrP(Sc)-specific antibodies, is used as a starting point for vaccine development. Through optimization of epitope, as well as formulation/delivery, we enhance immunogenicity while retaining PrP(Sc) specificity. In particular, QVYYRPVDQYSNQN, presented by a leukotoxin carrier protein, emerges as a strong vaccine candidate. A vaccine representing this construct induces consistent and sustained serum PrP(Sc)-specific IgG antibody responses following two vaccinations. Antigen specific antibodies are also present within cerebral spinal fluid and mucosal secretions. These characteristics provide a foundation for development of a TSE vaccine.