Unbiased interrogation of memory B cells from convalescent COVID-19 patients reveals a broad antiviral humoral response targeting SARS-CoV-2 antigens beyond the spike protein

• Published in: Vaccine: X 2021-08, Vol.8, p.100098-100098, Article 100098
• Main Authors: DiMuzio, Jillian M., Heimbach, Baron C., Howanski, Raymond J., Dowling, John P., Patel, Nirja B., Henriquez, Noeleya, Nicolescu, Chris, Nath, Mitchell, Polley, Antonio, Bingaman, Jamie L., Smith, Todd, Harman, Benjamin C., Robinson, Matthew K., Morin, Michael J., Nikitin, Pavel A.
• Format: Article
• Language: English
• Subjects: Antibody response; B cell repertoire; Convalescent plasma; COVID-19; Regular paper
• ISSN: 2590-1362; 2590-1362
• DOI: 10.1016/j.jvacx.2021.100098

Patients who recover from SARS-CoV-2 infections produce antibodies and antigen-specific T cells against multiple viral proteins. Here, an unbiased interrogation of the anti-viral memory B cell repertoire of convalescent patients has been performed by generating large, stable hybridoma libraries and screening thousands of monoclonal antibodies to identify specific, high-affinity immunoglobulins (Igs) directed at distinct viral components. As expected, a significant number of antibodies were directed at the Spike (S) protein, a majority of which recognized the full-length protein. These full-length Spike specific antibodies included a group of somatically hypermutated IgMs. Further, all but one of the six COVID-19 convalescent patients produced class-switched antibodies to a soluble form of the receptor-binding domain (RBD) of S protein. Functional properties of anti-Spike antibodies were confirmed in a pseudovirus neutralization assay. Importantly, more than half of all of the antibodies generated were directed at non-S viral proteins, including structural nucleocapsid (N) and membrane (M) proteins, as well as auxiliary open reading frame-encoded (ORF) proteins. The antibodies were generally characterized as having variable levels of somatic hypermutations (SHM) in all Ig classes and sub-types, and a diversity of VL and VH gene usage. These findings demonstrated that an unbiased, function-based approach towards interrogating the COVID-19 patient memory B cell response may have distinct advantages relative to genomics-based approaches when identifying highly effective anti-viral antibodies directed at SARS-CoV-2.