Development of a Bacteriophage Vaccine Vector System

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DESCRIPTION (provided by applicant): The goal of the studies in this proposal is to further develop a process that enables rapid production, purification and application of a bacteriophage vector system (BVS) platform expressing influenza A virus-like particles (Flu-VLPs). This goal is warranted as BVS is a unique vector that can be rapidly produced in bacteria, affords the safety profile associated with RNA-based vectors and has the potential for dual application as a transient expression system to produce subunit vaccines in vitro and as a vaccine vector directly administrable to humans or animals in vivo. BVS is derived from the double- stranded RNA (dsRNA) Cystovirus bacteriophage phi-8. To render this bacteriophage for vaccine applications the PI and coworkers have genetically altered genomic segment-S (gsS) and genomic segment-M (gsM) of phi-8, and launched the BVS recombinant phi-8 capsids in Escherichia coli host strains. In preliminary studies purified BVS capsids have been shown to express reporter proteins and vaccine antigens in mammalian cells in vitro. This background experience and evidence supports the proposal to further develop BVS capsids as a platform for emergency preparedness/biodefense applications. The PI provides justification that successful development of this system will create a public health tool and biodefense countermeasure, which under normal circumstances is capable of producing conventional subunit vaccines; yet, it is proposed that BVS capsids can be deployed as a vaccine vector from sequence identification through to vaccine release in under a month during emergency events where such a risk may be warranted. In this manner, this system integrates the advantages of manufacturing in bacteria and the utility and safety of non-replicating RNA-based nucleic acid vaccine vectors with the need for rapid response timelines to ensure broad emergency preparedness against emerging influenza virus serotypes such as H5N1. The central hypothesis that will be tested in the proposed studies below is that BVS capsids have the potential to serve as both a vaccine producer and vaccine vector. To address this hypothesis the PI proposes to (i) To develop a procedure to rapidly produce purified and bioactive BVS capsids that express Flu-VLPs and (ii) To characterize the immunogenicity of Flu-VLPs and BVS capsids expressing Flu-VLPs in laboratory animals. It is envisaged that successful completion of these aims will create an effective BVS capsid and Flu-VLP production system that can be adapted for manufacturing of both seasonal influenza and emerging influenza subtypes, and deployed significantly more rapidly than other vaccine modes. In addition, the proposed studies will provide fundamental information germane to the adaptation of this system to become an operational platform for rapid development and deployment of public health and biodefense vaccines. PUBLIC HEALTH RELEVANCE: A renewed awareness of the urgent need to devise strategies for the rapid development, manufacture and distribution of vaccines was invoked by the threat of avian influenza subtype H5N1 to spawn a catastrophic human pandemic and the increased threat of bioterrorism with other biological agents. The goal of the studies in this proposal is to provide a manufacturing platform that enables rapid production, purification and administration of vaccines. Furthermore, the studies herein will generate vaccine components and manufacturing procedures that will have an immediate utility in the control of both seasonal and pandemic influenza. Additionally, it is envisaged that this system will serve as an operational platform for rapid development and deployment of a broad array of public health and biodefense vaccines.