ELISpot assay and cytokine measurement
A total of 5×105 splenocytes were cultured together with the purified ZIKV-E antigen (10 μg/ml) in the 96-well ELISpot or U-bottom plate. For the ELISpot assay, cells were cultured for 24 h and detected using a commercial kit (MABTECH, Nacka, Sweden) according to the manufacturer’s instructions. For multiple cytokine measurement, cells were cultured for 72 h, and the supernatant was collected for detection using a Meso Scale Discovery (MSD) kit (Meso Scale Diagnostics, Rockville, MD, USA).