Fig 1. Efficient uptake of ZIKV immune complexes by ex-vivo perfused placentas.

1*10⁵ TCID₅₀ equivalent/mL inactivated ZIKV (ZIKV^BPL) was incubated with either flavivirus naïve serum or serum containing DENV-2 nAbs and added to the maternal circulation (MC) of the placental perfusion model and perfused for 40 or 120 minutes. A: Schematic overview of the ex vivo dual placental perfusion model. FC; fetal circulation. Created with Biorender.com. B: ZIKV RNA levels in the MC were determined every 15 minutes with RT-PCR up to 120 minutes to detect placental uptake of ZIKV^BPL. Dots represent mean ±SEM, N = 3–4 donors per condition. C: Mean fold reduction (+SEM) in ZIKV TCID₅₀ equivalent in the MC after 120 minutes of perfusion with and without different concentrations of protein G (Prot. G) to block the interaction of IgG with FcRn. N = 1–3 donors per condition. D: ZIKV RNA levels in the MC were determined every 10 minutes with RT-PCR up to 40 minutes. Dots represent mean±SEM, N = 2 donors per condition. E: ZIKV RNA was detected in tissue biopsies of the perfused placentas after 40 minutes of perfusion. Horizontal lines represent median and the 10^th and 90^th percentile cut-off. N = 2 donors per condition and 40 biopsies per condition. Data from the MC were analyzed with multiple t-tests with the Holm-Šidák correction and data from tissue lysates were analyzed with the Mann-Whitney U test. ****P<0.0001.