Neutralizing antibody vaccine for pandemic and pre-emergent coronaviruses

Betacoronaviruses caused the outbreaks of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome, as well as the current pandemic of SARS coronavirus 2 (SARS-CoV-2).sup.1-4. Vaccines that elicit protective immunity against SARS-CoV-2 and betacoronaviruses that circulate in animals have the potential to prevent future pandemics. Here we show that the immunization of macaques with nanoparticles conjugated with the receptor-binding domain of SARS-CoV-2, and adjuvanted with 3M-052 and alum, elicits cross-neutralizing antibody responses against bat coronaviruses, SARS-CoV and SARS-CoV-2 (including the B.1.1.7, P.1 and B.1.351 variants). Vaccination of macaques with these nanoparticles resulted in a 50% inhibitory reciprocal serum dilution (ID.sub.50) neutralization titre of 47,216 (geometric mean) for SARS-CoV-2, as well as in protection against SARS-CoV-2 in the upper and lower respiratory tracts. Nucleoside-modified mRNAs that encode a stabilized transmembrane spike or monomeric receptor-binding domain also induced cross-neutralizing antibody responses against SARS-CoV and bat coronaviruses, albeit at lower titres than achieved with the nanoparticles. These results demonstrate that current mRNA-based vaccines may provide some protection from future outbreaks of zoonotic betacoronaviruses, and provide a multimeric protein platform for the further development of vaccines against multiple (or all) betacoronaviruses. Immunization of macaques with nanoparticle-conjugated receptor-binding domain of SARS-CoV-2 adjuvanted with 3M-052 and alum results in cross-neutralizing antibodies against bat coronaviruses, SARS-CoV and SARS-CoV-2 variants, and may provide a platform for developing pan-coronavirus vaccines.
Author(s): Kevin O. Saunders [sup.1] [sup.2] [sup.3] [sup.4] , Esther Lee [sup.1] [sup.5] , Robert Parks [sup.1] [sup.5] , David R. Martinez [sup.6] , Dapeng Li [sup.1] [sup.5] , Haiyan [...]