Anti-SARS-CoV-2 Omicron Antibodies Isolated from a SARS-CoV-2 Delta Semi-Immune Phage Display Library

Ivette Mendoza-Salazar, Keyla M. Gómez-Castellano, Edith González-González, Ramsés Gamboa-Suasnavart, Stefany D. Rodríguez-Luna, Giovanni Santiago-Casas, María I. Cortés-Paniagua, Sonia M. Pérez-Tapia, Juan C. Almagro

Research output: Contribution to journalArticlepeer-review


This report describes the discovery and characterization of antibodies with potential broad SARS-CoV-2 neutralization profiles. The antibodies were obtained from a phage display library built with the VH repertoire of a convalescent COVID-19 patient who was infected with SARS-CoV-2 B.1.617.2 (Delta). The patient received a single dose of Ad5-nCoV vaccine (Convidecia™, CanSino Biologics Inc.) one month before developing COVID-19 symptoms. Four synthetic VL libraries were used as counterparts of the immune VH repertoire. After three rounds of panning with SARS-CoV-2 receptor-binding domain wildtype (RBD-WT) 34 unique scFvs, were identified, with 27 cross-reactive for the RBD-WT and RBD Delta (RBD-DT), and seven specifics for the RBD-WT. The cross-reactive scFvs were more diverse than the RBD-WT specific ones, being encoded by several IGHV genes from the IGHV1 and IGHV3 families combined with short HCDR3s. Six cross-reactive scFvs and one RBD-WT specific scFv were converted to human IgG1 (hIgG1). Out of the seven antibodies, six blocked the RBD-WT binding to angiotensin converting enzyme 2 (ACE2), suggesting these antibodies may neutralize the SARS-CoV-2 infection. Importantly, one of the antibodies also recognized the RBD from the B.1.1.529 (Omicron) isolate, implying that the VH repertoire of the convalescent patient would protect against SARS-CoV-2 Wildtype, Delta, and Omicron. From a practical viewpoint, the triple cross-reactive antibody provides the substrate for developing therapeutic antibodies with a broad SARS-CoV-2 neutralization profile.

Original languageEnglish
Article number13
Issue number1
StatePublished - Mar 2022


  • COVID-19
  • Phage display
  • Receptor-binding domain (RBD)
  • Therapeutic antibodies
  • VOCs


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