Figure 8

Infection enhancement of DENV mediated by 4D10, anti-PL10 sera and 4G2 in K562 cells. Serial 2-fold dilutions of antibody were incubated with an equal volume of DENV for 1 h at 37°C then transferred to K562 cells at MOI of 1. Infected K562 cells were determined by flow cytometry at 3 days post infection (A, B and C). Viral RNA copies of infected supernatants were measured by qRT-PCR at 4 days post infection (D, E and F). Both 4D10 and anti-PL10 sera could potently enhance infection of standard DENV1-4 and imDENV. NMS and IgG (mouse IgG1 and mouse IgG2a) isotype control antibodies were used as controls. Data are expressed as means of at least three independent experiments. The error bars represent standard deviations (SD). If there is no error bar, it is not that no variations among three independent experiments but that the variations are too small to show in the figure. * P < 0.05vs No Ab.