FIG 1.

Cell type-dependent neutralization of WNV. A GFP-expressing variant of an infectious lineage I WNV (39) was incubated with serial 5-fold dilutions of the indicated MAbs for 1 h at room temperature and then added to Vero, BHK-21 (BHK), or Raji-DC-SIGNR (RajiR) cells. Infectivity was measured as a function of GFP expression at 16 h postinfection using flow cytometry. Data were analyzed using nonlinear regression (GraphPad Prism). (A to H) Antibody dose-response curves generated with the DIII-lr-specific MAb E16 (A and E), the DII-fl-specific MAb E53 (B and F), the DII-hinge interface-specific MAb E113 (C and G), and the DI-lr-specific MAb E121 (D and H) are shown. Results are representative of four or five independent pairwise experiments conducted on Vero and RajiR cells or BHK and RajiR cells, respectively. Error bars represent the range of data from duplicate wells within a single experiment. (I and J) Summary of the fraction of infectious WNV resistant to neutralization at saturating concentrations of the indicated antibody when assayed pairwise on RajiR and Vero cells (I) or RajiR and BHK cells (J). Error bars represent standard errors from four or five independent experiments. The fractions of neutralization-resistant WNV on the different cell types were statistically evaluated using a paired t test.