Fig. 6

Rarely, DRG neurones and Schwann cells are positive for ZIKV in PNS cultures. a-d Micrographs of Ifnar1 knockout (KO) PNS cultures infected with an MOI of 3.0 for 72 hpi. a Overview of a NeuN and ZIKV-labelled culture to illustrate the low overall level of neuronal infection (green arrows indicate rare infected cells). Bar: 100 μm. b F480 positive macrophage in which green lipofuscin puncta can be mistaken for ZIKV immunostaining as indicated by the level of false ZIKV-positive macrophages observed in mock infected cultures. c ZIKV infected MBP-labelled Schwann cell (i) and infected and non-infected S100-labelled Schwann cells (ii and iii, respectively). d NeuN-labelled neurones, one of which is infected with ZIKV (green arrow). Bars: 20 μm. e-j Graphs of cell-type specific densities (grey bars) and infected cell densities (black bars) in wild type (WT) (e-g) and Ifnar 1 KO cultures (h-j). Many macrophages appeared positive for ZIKV in mock-infected cultures, suggesting that many of the macrophages quantified in (f, g, i and j) represent false positives. Bars represent mean ± SD; n = 3 for all graphs except mock infected wild type where n = 2