Figure 3
Affinity of cell surface-specific V H Hs to living C. reinhardtii cells. Live-cell ELISA analyses comparing binding affinities to C. reinhardtii cells of various E-tag VHHs (B11, blue line; H10, red line; C3, green line); and VHH B5 (a VHH binding specifically to a Clostridium botulinum BoNT/B holotoxin; negative control) purple line. Cells were incubated with serial dilutions of E-tag VHHs at concentrations from 2 μM to 20 pM. E-tag VHH nanobodies attached to Chlamydomonas cells were detected using a HRP conjugated E-tag antibody that reacted with TMB (3,3′,5,5′-tetramethylbenzidine) to measure amounts of VHH bound to cell surface antigens. Error bars represent standard deviation.