PROJECT SUMMARY – PROJECT 5: mRNA AND mRNA-LAUNCHED NANOPARTICLE VACCINES The goal of Project 5 is to develop generalizable approaches and platforms to design, make, and evaluate mRNA-based vaccines for paramyxovirus, arenavirus, and phenuivirus antigens. We will leverage the industry experience of Stuart in mRNA vaccines with the King lab’s leadership in structure-based vaccine design. We will define strategies to optimize the designed antigens from Project 3 to further improve their performance when delivered by mRNA. Additionally, we will combine the speed of mRNA vaccine manufacture with the potency of nanoparticles to develop an mRNA-launched nanoparticle vaccine platform. This work will be made possible by application of cutting-edge machine learning-based methods for protein design from the Baker lab and deep pathogen-specific expertise in the Broder, Cross, Freiberg, Geisbert, Ikegami, and Veesler groups. The central hypothesis underlying our approach is that mRNA vaccines will only realize their full potential when combined with cutting-edge protein design. Specifically, proteins designed for optimal secretion and localization within the membrane can improve immunogenicity. Additionally, using mRNA vaccines to launch genetically encoded protein nanoparticle immunogens from cells in vivo can enhance the potency and durability of the response. In summary, we will leverage the computational tools and methods developed in Project 1, along with the antigen and nanoparticle design work from Projects 3 and 4, to develop new, generalizable strategies for mRNA vaccine design for arenaviruses, phenuiviruses, and paramyxoviruses. In Years 4-5, we will explicitly test if these strategies can be generalized to other members of these viral families in a “live-fire exercise” intended to mimic an outbreak situation.