Figure 3

Enhancing activity assay of monkey anti-DENV sera using the new assay system. Samples #175 and #052 were obtained from subjects positive to DENV, and #NS (negative serum) was a sample from healthy subject as a negative control. Sera in various dilutions were mixed with Luc-DENV and incubated for 72 h. Luciferase activities were measured in lysed K562 cells to assay enhancing activities. Error bars indicate the standard deviations from two independent experiments.