Fig. 4.

MTT assay allows quantification of the virus neutralization capacity of antisera from ZVD patients. Negative control sera or sera positive for ZIKV (ZIKV+), Dengue (DENV+), or tick-borne encephalitis virus (TBEV+) IgG and IgM antibodies (Table 1) were diluted and incubated for 90 min with 1 × 10⁶ TCID₅₀/ml of the lab-adapted ZIKV strain MR766 (a) or the recent clinical isolate GWUH (b). Thereafter, 180 µl Vero E6 cells were infected with 20 µl of the virus/antisera samples, and 4 days later MTT assay was performed. Shown is the percentage of virus-induced dead cells obtained from triplicate infections ± standard deviation. Shown on the x-axis are the final cell culture concentrations of the sera in %