The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern threatens the efficacy of existing vaccines and therapeutic antibodies and underscores the need for additional antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells collected from patients with coronavirus disease 2019. The three most potent antibodies targeted distinct regions of the receptor binding domain (RBD), and all three neutralized the SARS-CoV-2 Alpha and Beta variants. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the angiotensin-converting enzyme 2 receptor, and has limited contact with key variant residues K417, E484, and N501. We designed bispecific antibodies by combining nonoverlapping specificities and identified five bispecific antibodies that inhibit SARS-CoV-2 infection at concentrations of less than 1 ng/ml. Through a distinct mode of action, three bispecific antibodies cross-linked adjacent spike proteins using dual N-terminal domain–RBD specificities. One bispecific antibody was greater than 100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a dose of 2.5 mg/kg. Two bispecific antibodies in our panel comparably neutralized the Alpha, Beta, Gamma, and Delta variants and wild-type virus. Furthermore, a bispecific antibody that neutralized the Beta variant protected hamsters against SARS-CoV-2 expressing the E484K mutation. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.
【초록키워드】 coronavirus disease, SARS-CoV-2, Efficacy, Vaccine, coronavirus, antibody, monoclonal antibody, variant, SARS-CoV-2 variant, Infection, variants of concern, in vitro, delta variant, angiotensin-converting enzyme 2, variants, Spike protein, Receptor binding domain, specificity, Region, RBD, therapeutic, Patient, Gamma, Beta, receptor, E484K mutation, hamster, memory B cell, monoclonal, Concentration, dose, Contact, SARS-CoV-2 RBD, acute respiratory syndrome, residue, plasmablast, wild-type virus, K417, Specificities, clinical disease, N-terminal, FIVE, neutralize, neutralized, bind, greater, collected, less, the spike protein, prevented, expressing, inhibit SARS-CoV-2, the SARS-CoV-2, 【제목키워드】 antibody, SARS-CoV-2 variant, Region, neutralize, the spike protein,