Fig. 11

Association of PrPSc with cone bipolar cells. a Confocal z-stack of an uninfected retina shows secretagogin-positive cone bipolar cell bodies (magenta arrows) and their green dendritic processes associated with PrP (magenta) in dense clusters (yellow arrows) which include short ribbon synapses (yellow). b A single confocal section taken from the box in panel a shows PrP in close association with cone bipolar cell dendrites (green), beneath clusters of short ribbons (yellow) typically found in cone pedicles. Horseshoe-shaped ribbons in rod spherules (blue arrows) are not associated with PrP or SCGN. c In a confocal z-stack, at 118 dpi, cone bipolar cell bodies (magenta arrow) appear normal but PrP staining is increased in the OPL. d A single confocal section taken from the box in panel c shows increase in PrP among the SCGN-positive dendrites with some PrP overlapping SCGN, suggesting colocalization (white arrow). PrP is also present within the horseshoe-shaped ribbon synapses in rods (blue arrows). e, f Widefield images at 104 dpi show numerous examples of PrP clusters localizing with the ends of SCGN-positive dendrites (blue arrows) originating from cone bipolar cells (magenta arrows). g Number of cone bipolar cells per mm vs dpi. Each symbol represents the count from one field of view. Different symbols represent different animals. Line represents median. h–k anti-Secretagogin stained retina from uninfected and three different dpi show relative numbers of SCGN-positive cells. ns = not significant, statistics by one-way ANOVA with multiple comparisons test. Scale bars: a, c = 4 µm; b, d = 1 µm; e,f = 10 µm; h–k = 25 µm