Project Summary/Abstract – Project 5: Multi-scale development and evaluation of broadly-effective vaccines against picornaviruses with pandemic potential Picornaviruses are the most common causes of viral illnesses worldwide. Within the picornavirus family of positive-strand RNA viruses, enteroviruses such as poliovirus, coxsackievirus, enterovirus A71 (EV-A71), and enterovirus D68 (EV-D68) have the potential to produce devastating disease sequelae in humans, including paralytic poliomyelitis, cardiomyopathy, pancreatitis, encephalitis, meningitis, and acute flaccid myelitis (AFM). Surprisingly, the only enterovirus vaccines with U.S. FDA approval are the highly successful inactivated and attenuated vaccines against poliovirus. In addition, there are no approved antiviral drugs to successfully treat enterovirus infections despite their considerable pandemic potential. The availability of phylogenetically- conserved, structure-based design approaches across a large number of related enteroviruses provides a range of new opportunities to generate a comprehensive panel of mRNA- and protein-based vaccine candidates to combat infection by these important human pathogens. The experimental approach for this project involves the testing of mRNA and protein/adjuvant vaccine candidates using in vitro virus culture and animal challenge/pathogenesis models. The proposed project will also explore novel approaches to vaccine design and construction that leverage the unique features of picornavirus biology to generate lead strategies that may prove broadly effective. The proposal will also employ state-of-the-art murine models for evaluating vaccine efficacy and protection from disease. This standardized series of in vivo models will provide a unique opportunity to compare efficacy of vaccine responses across different enterovirus serotypes and species and identify the most promising candidates for advancement to large animal models. Collectively, the breadth of experiments proposed will create a validated workflow for developing and testing new vaccines that are designed to provide broad protection against multiple different known pathogenic picornaviruses. Importantly, when combined with the other cores and projects in this application, this approach is predicted to allow the rapid development and preclinical evaluation of vaccines and nanobody therapeutics to any new picornavirus that emerges and represents a significant public health concern.