Single-component multilayered self-assembling nanoparticles presenting rationally designed glycoprotein trimers as Ebola virus vaccines

Ebola virus (EBOV) glycoprotein (GP) can be recognized by neutralizing antibodies (NAbs) and is the main target for vaccine design. Here, we first investigated the contribution of the stalk and heptad repeat 1-C (HR1C) regions to GP metastability. Specific stalk and HR1C modifications in a mucin-deleted form (GPDmuc) increased trimer yield, whereas alterations of HR1C exerted a more complex effect on thermostability. Crystal structures were determined to validate two rationally designed GPDmuc trimers in their unliganded state. We then displayed a modified GPDmuc trimer on reengineered nanoparticles that encapsulated a layer of locking domains (LD) and a cluster of helper T-cell epitopes. In mice and rabbits, GP trimers and nanoparticles elicited cross-ebolavirus NAbs, as well as non-NAbs that enhanced pseudovirus infection. Repertoire sequencing revealed quantitative profiles of vaccine-induced B-cell responses. This study demonstrates a promising vaccine strategy for filoviruses, such as EBOV, based on GP stabilization and nanoparticle display.