Fig. 1: In vitro characterization of antibody 5B11.

a–d The binding activity of 5B11 to the purified recombinant pre-F (DS-Cav1) and post-F from RSV A2 (a) and RSV B18537 (b) was measured by indirect ELISA. Data represents one of three independent experiments, shown as mean ± standard deviation (SD) of three technical replicates. Palivizumab (Pali.) was used as a positive control. EC₅₀ (ng/mL) was calculated to assess the binding potency of 5B11 with RSV F protein. The binding affinities of 5B11 with RSV-A (c) and -B (d) DS-Cav1s were identified by surface plasmon resonance (SPR). e–i Neutralizing potency of RSV nAbs were measured by RSV plaque reduction neutralization assay and determined by IC₅₀ values (ng/mL), which indicated the concentration of nAbs required for reducing 50% of viral infection. Neutralization activities of 5B11 (strawberry), h5B11 (carnation), 1129 (blueberry), palivizumab (orchid) and nirsevimab (aluminum) against RSV laboratory strain A2 (e), Long (f), B9320 (g) and B18537 (h) were determined, respectively. Data represents one of three independent experiments, shown as mean ± SD of two technical replicates. i A panel of 15 RSV-A (n = 15) and 10 RSV-B clinical isolates (n = 10) was also tested in the neutralization assay. Data represents one of three independent experiments. Horizontal bars in (i) indicate geometric mean IC₅₀. j, k Attachment inhibition (j) and fusion inhibition assays (k) for 5B11 and other RSV F-specific antibodies. In the attachment inhibition assay, heparin sodium served as a positive control. Data in (j) and (k) are representative of three independent experiments. Source data are provided as a Source Data file.