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Highlights: [•] Silica nanoparticles were used to adjuvant sub-unit protein antigen. [•] Nanoparticles boosted antigen immune response without protein conjugation. [•] Non-carrier nanoparticles adjuvanting efficacy depends on particle size. [ABSTRACT FROM AUTHOR]

Abstract: Faster and cheaper vaccine manufacture based on modern technologies is increasingly needed to effectively mitigate the burden of disease caused by highly contagious and mutagenic pathogens, such as influenza viruses. This study describes an approach to synthetically engineer a new influenza vaccine system by antigenic modularization of a carrier viral capsomere, coupled with microbial processing of the sub-unit vaccine. This approach leads to a system optimized with respect to both biological and process criteria. Murine polyomavirus VP1 protein, which self assembles into a pentameric sub-unit capsomere of a virus-like particle (VLP), was engineered to inhibit VLP assembly and to allow modular insertion of influenza M2e antigen at multiple sites within the protein. The yield, solubility, and immunogenicity of the resulting modular capsomeres could be optimized by varying the module insertion site and the number of M2e modules per site. This study demonstrated, for the first time, an innovative strategy of inserting multiple antigenic modules, up to 45 M2e modules, in a single capsomere. Modularization of M2e antigen was shown to improve its immunogenicity by more than an order of magnitude over that attained by immunization with an equivalent mass of non-modularized M2e peptide. Vaccination of mice using modular capsomeres induced high antigen-specific antibody levels suggestive of protective efficacy. This modular vaccine design approach, inspired by synthetic biology approaches to new system development, is conducive to technologies rapidly adaptable to pathogenic variations. [Copyright &y& Elsevier]

Highlights: [•] Helix 190 (H190) from influenza virus modularized onto unrelated polyomavirus VLP. [•] Antigen module design affected response quality (level of binding to HA1). [•] Flanking H190 element with GCN4 gave a low-quality response (low HA1 binding). [•] Modularizing multiple tandem repeats of H190 gave a high-quality antibody response. [•] Biomolecular engineering offers a future alternative to whole pathogen vaccines. [ABSTRACT FROM AUTHOR]

Abstract: Group A streptococcus (GAS) causes a wide range of diseases, some of them related to autoimmune diseases triggered by repeated GAS infections. Despite the fact that GAS primarily colonizes the mucosal epithelium of the pharynx, the main mechanism of action of most vaccine candidates is based on development of systemic antibodies that do not cross-react with host tissues, neglecting the induction of mucosal immunity that could potentially block disease transmission. Peptide antigens from GAS M-surface protein can confer protection against infection; however, translation of such peptides into immunogenic mucosal vaccines that can be easily manufactured remains a challenge. In this work, a modular murine polyomavirus (MuPyV) virus-like particle (VLP) was engineered to display a GAS antigenic peptide, J8i. Heterologous modules containing one or two J8i antigen elements were integrated with the MuPyV VLP, and produced using microbial protein expression, standard purification techniques and in vitro VLP assembly. Both modular VLPs, when delivered intranasally to outbred mice without adjuvant, induced significant titers of J8i-specific IgG and IgA antibodies, indicating significant systemic and mucosal responses, respectively. GAS colonization in the throats of mice challenged intranasally was reduced in these immunized mice, and protection against lethal challenge was observed. This study shows that modular MuPyV VLPs prepared using microbial synthesis have potential to facilitate cost-effective vaccine delivery to remote communities through the use of mucosal immunization. [Copyright &y& Elsevier]

Abstract: Studies on a platform technology able to deliver low-cost viral capsomeres and virus-like particles are described. The technology involves expression of the VP1 structural protein from murine polyomavirus (MuPyV) in Escherichia coli, followed by purification using scaleable units and optional cell-free VLP assembly. Two insertion sites on the surface of MuPyV VP1 are exploited for the presentation of the M2e antigen from influenza and the J8 peptide from Group A Streptococcus (GAS). Results from testing on mice following subcutaneous administration demonstrate that VLPs are self adjuvating, that adding adjuvant to VLPs provides no significant benefit in terms of antibody titre, and that adjuvanted capsomeres induce an antibody titre comparable to VLPs but superior to unadjuvanted capsomere formulations. Antibodies raised against GAS J8 peptide following immunization with chimeric J8-VP1 VLPs are bactericidal against a GAS reference strain. E. coli is easily and widely cultivated, and well understood, and delivers unparalleled volumetric productivity in industrial bioreactors. Indeed, recent results demonstrate that MuPyV VP1 can be produced in bioreactors at multi-gram-per-litre levels. The platform technology described here therefore has the potential to deliver safe and efficacious vaccine, quickly and cost effectively, at distributed manufacturing sites including those in less developed countries. Additionally, the unique advantages of VLPs including their stability on freeze drying, and the potential for intradermal and intranasal administration, suggest this technology may be suited to numerous diseases where adequate response requires large-scale and low-cost vaccine manufacture, in a way that is rapidly adaptable to temporal or geographical variation in pathogen molecular composition. [Copyright &y& Elsevier]