Fig. 3.

Fluorescent micrographs of sagittal cryosections from 17 pcw human foetal olfactory system immunolabelled with antibodies towards P75^NTR (green), S100 (red), SOX10 (magenta), and DAPI nuclear stain (blue). a Axioscan micrograph montages of the olfactory bulb (OB) and olfactory nerves (ON, asterisk). Scale bar 500 μm. S100 labels the entire olfactory nerve layer (ONL) and ONs, whereas P75^NTR surrounds the outside of the OB and ONs. P75^NTR labelling was also observed surrounding blood vessels (blue arrowhead); on cells within the nasal stroma (white arrowheads) and intensely expressed in meningeal tissue (yellow arrowhead). b Cross-section of olfactory nerves showing P75^NTR+ processes (white arrows) surrounding S100+ OECs. b1 Scale bar 100 μm. b2–4 Scale bar 20 μm, shows magnified images of area within white box in b1. c2–7 Serial optical sections through a 13 μm z-stack (c1) showing DAPI labelled nuclei and P75^NTR+ processes of perineurial cells (white arrows) surrounding S100+ OECs within a cross-section of an olfactory nerve (asterisk). Scale bar 20 μm. d1–3 In the outer ONL, P75^NTR is expressed on cells (white arrowheads) surrounding ONs as they enter the ONL, but not on SOX10/S100+ OECs. Dashed white lines show rough boundary of ONL, scale bar 20 μm. e P75^NTR+ cells surround presumptive arterioles in the ONL, scale bar 20 μm