Fig. 2.

Selection of SARS-CoV-2 RBD–specific nanobodies. (A) FACS workflow to enrich populations in antigen-specific clones. Cells in AFF1, AFF2, and AFF3 are labeled with 100 nM biotinylated RBD to depict the enrichment overtime. Cells in PSR1 and PSR2 are labeled with biotinylated PSR preparation. The RBD and PSR concentrations used for sorting are indicated in SI Appendix, Text. (B) ELISA plot showing Fc-fused LM18, LM44, LM45, and LM46 binding to SARS-CoV-2 RBD. CC6.30 was used as a positive control and a nanobody-Fc from our library not selected for RBD binding was used as a negative control. The assay was run in duplicate. (C) Neutralization assay of Wuhan-1 SARS-CoV-2 PSV for the four nanobodies tested showing neutralization by LM18. Assay was run in triplicate. Error bars indicate the SD of the mean.