Rhesus monkeys (N=4/group) received 10 mg/kg B10 or the isotype matched sham control antibody PGT121 by the i.v. route on day −1 or day +2. All animals were challenged on day 0 by the s.c route with 106 VP (103 PFU) ZIKV-BR. Viral loads are shown in (a) plasma, (b) cerebrospinal fluid (CSF), and (c) lymph nodes (LN). Viral loads were determined on days 0, 1, 2, 3, 4, 5, and 7 for the plasma samples and on days 0, 3, 7, 14, and 35 for the other samples. Assay sensitivity 100 copies/ml or 1×106 cells. Arrows designate the day +2 infusions.