Figure 3.

Mechanisms for DENV entry into B cells. (A) CD19⁺ B cells were isolated from PBMCs from healthy donors (n = 4) by magnetic sorting, incubated with different concentrations of blocking antibody against CD300a or isotype control antibody and infected with reference DENV-1 or DENV-2 strains at MOI 20. At 24 h post infection, cells were stained with anti-DENV NS3 antibody. Percentage of infection is represented with respect to isotype control. (B, C) Monoclonal antibody G10 or serum from patient with DENV-2 infection was serially diluted five-fold (1:100 to 1:1,562,500) in RPMI and incubated with DENV-1 virions corresponding to MOI of 1 for 1 h at 37°C, 5% CO₂. These immune complexes were then transferred to U937 cells and B cells and incubated for 90 min at 37°C, 5% CO₂. Direct infection with DENV in the absence of G10 antibody or patient serum was used as control. At 72 h post infection, cells were fixed, permeabilized, and stained with anti-E antibody (clone 4G2). Fold change is represented for each dilution with respect to direct infection. Bars represent mean and SEM, where the experiment was replicated with three different healthy donors. (*P < 0.05).