Figure 1: F-VHHs with potent RSV-neutralizing activity. | Nature Communications

Figure 1: F-VHHs with potent RSV-neutralizing activity.

From: Potent single-domain antibodies that arrest respiratory syncytial virus fusion protein in its prefusion state

Figure 1

RSV-neutralizing activity by F-VHHs. (a) RSV A2 (50 pfu per well) or (b) RSV B49 (40 pfu per well) was preincubated with different concentrations of VHH before infection of Vero cells. Three days later, the viral plaques were stained with polyclonal anti-RSV serum. (c) Amino acid sequences of F-VHH-4 and F-VHH-L66 with Kabat numbering. The complementarity-determining regions (CDRs) are boxed. Cysteines in CDR2 and CDR3 are in bold. (d) RSV A2 (30 pfu per well) plaque-reduction activity of F-VHH-4 and F-VHH-L66 compared with mAbs. The Ctrl-VHH is specific for an irrelevant target. (e) IC50 values of F-VHHs and mAbs against RSV A2 and RSV B49 as determined by plaque-reduction assay. Mean values±s.d. from four (VHHs), three (D25) or two (palivizumab, motavizumab and AM22) repeat experiments are depicted for RSV A. Mean values±s.d. from two experiments are depicted for RSV B. ND: Not determined. (f) Dilution series of VHHs and mAbs were added to HEp-2 cells that had been preincubated with RSV A2 (25 pfu per well) at 4 °C for 2 h, allowing viral attachment. After 2 h at 37 °C, the VHHs or antibodies were washed away and infection was allowed during two days at 37 °C after which the plaques were stained. Antibody, 65 is a mouse IgG2a monoclonal antibody that is specific for an irrelevant antigen.

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