Immunofluorescence analysis (IFA)
For detection of the ZIKV-E protein, Sf9 cells were seeded in 24-well plates and infected with recombinant baculovirus at an MOI of 0.5. Forty-eight hours later, the cells were fixed with 70% cold ethanol and stained with an anti-flavivirus E mAb (1:200) as the primary antibody. Then, a FITC-conjugated anti-mouse antibody (1:200) and Evans blue (1:300) were used. Fluorescence was observed under a fluorescence microscope (Olympus Corp, Tokyo, Japan).