Figure 3. DENV plasma enhances ZIKV infection.
(a) Flow cytometric profiles of U937 cells infected with ZIKV strains PF13 and HD78788 and DENV serotype 2 in the absence or presence of 1:10,000 PCS (the dilution giving peak enhancement) demonstrating the low background infection. (b) ADE curves (fold increase in FFU) of U937 cells infected with ZIKV (strain PF13 and HD78788) and DENV serotype 2 using PCS and PND. (c) Six representative ADE curves (fold increase in FFU) of U937 cells infected with ZIKV strains PF13 and HD78788 and DENV (6-month convalescent plasma using the DENV serotype 2 in the presence of serially diluted DENV plasma). PND was used as negative control (closed circles). (d) Peak fold enhancement (fold increase in FFU) of DENV plasma on ZIKV and DENV (n=16). Small horizontal lines indicate the median values.