A Dynamic Landscape for Antibody Binding Modulates Antibody-Mediated Neutralization of West Nile Virus
Figure 4
Time- and temperature-dependent increases in neutralization by antibodies that bind cryptic determinants on the mature virion.
Nine serial four-fold dilutions of the DII-fusion loop (fl)-reactive MAb E53 (A and B) or the DI-reactive MAb E121 (C) were incubated with mature WNV RVPs for one hour at room temperature to allow binding to reach equilibrium. RVP-antibody complexes were then incubated at 37°C only (A) or at 33°C, 37°C, and 40°C (B and C) for incremental lengths of time before infecting Raji-DC-SIGNR cells. Infectivity was carried out at 37°C and monitored by flow cytometry at 48 h post-infection. The reference curve represents RVP-antibody complexes added to Raji-DC-SIGNR cells immediately after the room temperature incubation. Dose-response curves from representative experiments are expressed relative to the infectivity of RVPs in the absence of antibody at each individual time point. Error bars display the standard error of duplicate infections. Results are representative of five and three independent experiments for MAb E53 and E121, respectively.