ChBE Seminar Series: Rapid isolation, characterization and engineering of second-generation SARS-CoV
Speaker: Jordan Woehl, Protein Scientist, International AIDS Vaccine Initiative
Title: Rapid isolation, characterization and engineering of second-generation SARS-CoV-2 antibodies with increased binding affinity and neautralization potency
Recent developments in antibody technology allowed for rapid identification and development of neutralizing antibodies against SARS-CoV-2 as a therapeutic in order to combat the growing pandemic. We enrolled a cohort of severe SARS-CoV-2-recovered patients, developed neutralization assays, adapted our high-throughput antibody generation pipeline to rapidly screen more than 1800 antibodies, and established an animal model to test protection. We isolated potent neutralizing antibodies (nAbs) to two epitopes on the receptor binding domain (RBD) and to distinct non-RBD epitopes on the spike (S) protein. The most potent nAbs tend to bind to an epitope on RBD that blocks the Angiotensin-Converting Enzyme 2 (ACE2) binding and disrupts the initial viral attachment to the target cell. First generation antibodies recovered were done so from timepoints fairly close to the time of infection or immunization, having very few mutations and typically bound to RBD with a dissociation constant between 1 and 10 nM measured by surface plasmon resonance (SPR). Using a yeast surface display method in combination with fluorescence activated cell sorting (FACS), we affinity matured a collection of first generation antibodies for enhanced binding affinity for SARS-CoV-2 S and/or RBD. The higher affinity antibodies neutralize SARS-CoV-2 pseudovirus and live virus with enhanced potency, and show protection in animals at lower serum concentrations. These second generation antibodies are promising prophylactic and therapeutic lead candidates and enable us to explore the relationship between binding affinity, in vitro neutralization, and in vivo protection of SARS-CoV-2.
Dr. Woehl is a protein scientist with the International AIDS Vaccine Initiative (IAVI) in La Jolla, CA. He has degrees in medicinal chemistry from the University of Missouri (B.S. 2011), cell & molecular biology from the University of Missouri-Kansas City (M.S. 2013), and biochemistry & molecular biophysics from Kansas State University (Ph.D. 2017), where his research focused on the structural and functional relationship between Staphylococcus aureus virulence factors and the human innate immune system. He was a postdoctoral fellow at The Scripps Research Institute, focusing on the screening, development, and characterization of small molecule inhibitors and activity-based probes against human and bacterial proteolytic targets. His current research/position at IAVI focuses on the discovery, engineering, and characterization of broadly neutralizing antibodies for use in therapeutics against novel/neglected infectious diseases, as well as aid in the design of immunogens to elicit neutralizing antibodies through vaccination.