Engineering a Rugged NanoscaffoldTo Enhance Plug-and-DisplayVaccination

摘要

Nanoscale organization is crucial to stimulating an immune response. Using self-assembling proteins as multimerization platforms provides a safe and immunogenic system to vaccinate against otherwise weakly immunogenic antigens. Such multimerization platforms are generally based on icosahedral viruses and have led to vaccines given to millions of people. It is unclear whether synthetic protein nanoassemblies would show similar potency. Here we take the computationally designed porous dodecahedral i301 60-mer and rationally engineer this particle, giving a mutated i301 (mi3) with improved particle uniformity and stability. To simplify the conjugation of this nanoparticle, we employ a SpyCatcher fusion of mi3, such that an antigen of interest linked to the SpyTag peptide can spontaneously couple through isopeptide bond formation (Plug-and-Display). SpyCatcher-mi3 expressed solubly to high yields in Escherichia coli, giving more than 10-fold greater yield than a comparable phage-derived icosahedral nanoparticle, SpyCatcher-AP205. SpyCatcher-mi3 nanoparticles showedhigh stability to temperature, freeze–thaw, lyophilization,and storage over time. We demonstrate approximately 95% efficiencycoupling to different transmission-blocking and blood-stage malariaantigens. Plasmodium falciparum CyRPA was conjugatedto SpyCatcher-mi3 nanoparticles and elicited a high avidity antibodyresponse, comparable to phage-derived virus-like particles despitetheir higher valency and RNA cargo. The simple production, precisederivatization, and exceptional ruggedness of this nanoscaffold shouldfacilitate broad application for nanobiotechnology and vaccine development.