ZIKV-116 neutralizes DENV1 strain 16007 better than West Pac-74. (A) ZIKV-116 or control mAbs (WNV-E111 [flavivirus cross-reactive] and DENV4-E88 [DENV4 type-specific]) were tested for binding to the indicated flavivirus proteins (ZIKV E, ZIKV E-FL [mutant strain of H/PF/2013], ZIKV DIII [strains of H/PF/2013 and MR-766], WNV E and DIII, SPOV E [Spondweni virus], and DENV1–4 DIII) as indicated in ELISA. (B) ZIKV-116 or control mAbs (JEV-106 [JEV DIII-specific] and POWV-61 [Powassan DIII-specific]) were tested for binding to the indicated DIII of ZIKV H/PF/2013, JEV, and POWV. The results are representative of two independent experiments performed in triplicate. (C) Neutralization curves of DENV2 (D2S20) and DENV1 (16007 and West Pac-74 [WP]) by ZIKV-116 and control mAb DENV1-E111. The indicated virus was incubated with serial-diluted mAbs for 1 h at 37°C followed by addition of the mixture to Vero cells. Then, FRNT assays were performed, and the percentage of infection was calculated by comparing to no mAb–treated wells. Data were pooled from two or more independent experiments performed in triplicate or quadruplicate.