ABSTRACT The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein mediates viral entry into cells expressing angiotensin-converting enzyme 2 (ACE2). The S protein engages ACE2 through its receptor-binding domain (RBD), an independently folded 197-amino-acid fragment of the 1,273-amino-acid S-protein protomer. The RBD is the primary SARS-CoV-2 neutralizing epitope and a critical target of any SARS-CoV-2 vaccine. Here, we show that this RBD conjugated to each of two carrier proteins elicited more potent neutralizing responses in immunized rodents than did a similarly conjugated proline-stabilized S-protein ectodomain. Nonetheless, the native RBD is expressed inefficiently, limiting its usefulness as a vaccine antigen. However, we show that an RBD engineered with four novel glycosylation sites (gRBD) is expressed markedly more efficiently and generates a more potent neutralizing responses as a DNA vaccine antigen than the wild-type RBD or the full-length S protein, especially when fused to multivalent carriers, such as a Helicobacter pylori ferritin 24-mer. Further, gRBD is more immunogenic than the wild-type RBD when administered as a subunit protein vaccine. Our data suggest that multivalent gRBD antigens can reduce costs and doses, and improve the immunogenicity, of all major classes of SARS-CoV-2 vaccines.
【저자키워드】 COVID-19, SARS-CoV-2, ACE2, Vaccine, ferritin, Receptor-binding domain, RBD, 【초록키워드】 coronavirus, S protein, SARS-CoV-2 vaccines, angiotensin-converting enzyme 2, viral entry, SARS-CoV-2 vaccine, Antigen, Protein, Neutralizing, epitope, rodent, Critical, DNA vaccine, S-protein, Helicobacter pylori, acute respiratory syndrome, subunit, carriers, domain, immunogenic, wild-type, ectodomain, doses, vaccine antigen, full-length S protein, Administered, Cell, immunized, glycosylation site, IMPROVE, generate, expressed, expressing, elicited, engage, fused, neutralizing response, reduce cost, 【제목키워드】 immunogenicity, multivalent,