Proactive vaccination using multiviral Quartet Nanocages to elicit broad anti-coronavirus responses

Defending against future pandemics requires vaccine platforms that protect across a range of related pathogens. Nanoscale patterning and efficient molecular self-assembly are key to the success of new vaccine approaches. Here we produce quartets of concatenated receptor-binding domains (RBDs) from a panel of SARS-like betacoronaviruses, precisely coupled to the computationally-designed mi3 nanocage through SpyTag/SpyCatcher spontaneous reaction. These Quartet Nanocages, possessing a branched morphology, induce a high level of neutralizing antibodies against several different coronaviruses, including against viruses not represented on the vaccine. Equivalent antibody responses are raised to RBDs close to the nanocage or at the tips of the nanoparticle’s branches. In animals primed with SARS-CoV-2 Spike, boost immunizations with Quartet Nanocages increase the strength and breadth of an otherwise narrow immune response. A Quartet Nanocage including the Omicron XBB.1.5 “Kraken” RBD induced antibodies with binding to a broad range of sarbecoviruses, as well as neutralizing activity against this Variant of Concern. Quartet Nanocages are a nanomedicine approach with potential to confer heterotypic protection against emergent zoonotic pathogens and facilitate proactive pandemic protection.