Figure 1.
SARS-CoV-2 is propagating in human placenta PCSs
(A) Placenta PCSs were prepared as slices of 500–700 μm and challenged with SARS-CoV-2 at a rate of 5 × 105 PFU per slice and analyzed 24–120 h p.i.
(B) Representative stereomicroscopic image showing a preserved villous microstructure of placenta PCSs after 120 h of culture. Scale bar, 500 μm.
(C) Representative 3D rendering micrograph of the syncytiotrophoblast (BLC-2, green) and trophoblast (TROP-2, red) layers in placenta PCS cultures. DAPI (blue). Scale bar, 30 μm.
(D) WD-NECs were infected apically with 5 × 104 PFU per insert. The infectious virus release was evaluated in apical washes 24 to 72 h p.i. Each symbol represents an individual donor (n = 3). The input indicates the virus titer adjusted to the volume of inoculum and the horizontal dashed line indicates the baseline measured in mock controls and defined as the detection limit of the PFU assay.
(E) Shedding of infectious virus over time by placenta PCSs exposed to 5 × 105 PFU of SARS-CoV-2. Each symbol represents an individual donor (n = 7). The input indicates the virus titer adjusted to the volume of inoculum and the horizontal dashed line indicates the baseline in mock controls and defined as the detection limit of the PFU assay.
(F) ACE2 and TMPRSS2 mRNA expression levels in non-infected WD-NECs and placenta PCS cultures. Boxplots indicate the median value (centerline) and interquartile ranges (box edges), with whiskers extending to the lowest and the highest values. Each symbol represents an individual donor (n = 3 and n = 7, respectively).
(G and H) Correlation of SARS-CoV-2 titers 120 h p.i. of placenta PCSs and ACE2 (G) and TMPRSS2 (H) mRNA levels. Associations were tested using the Spearman rank correlation test. Each symbol represents an individual donor (n = 7).