Figure 1

DENV-2 infection of K562 cells. Prior to infection of mice and mosquitoes, DENV-2 is propagated in K562 cells at MOI 1.0 in the presence of antibody against DENV-4. After incubation for 2 h in 37°C, cells are centrifuged, then resuspended in an equivalent volume of fresh medium containing antibody against DENV-4. The mixture then is incubated for two days at 37°C.