Exosome-Producing Follicle Associated Epithelium Is Not Involved in Uptake of PrPd from the Gut of Sheep (Ovis aries): An Ultrastructural Study
Figure 2
Ultrastructural observations of the follicle associated epithelium (FAE) at early time points (15 minutes to 3.5 hours postinoculation).
(a, b, and e) 15 minutes to 2 hours post exposure to inoculum granular material, membranous whorls and vesicles were observed in the lumen. (a) The short surface projections of the FAE (arrowheads) contrast with the prominent brush border of the AE. The interdigitating lateral cell contacts of the FAE are also conspicuous (arrows). In contrast to the AE, FAE showed a high activity rate with many vesicles and branching tubular structures in the apical portion of the cells at early time points post inoculation (animal R1292 2 hour sucrose loop). (b) Higher magnification of FAE showing MVBs (arrowheads), vesicles and branching tubular structures in apical portions of the cell (animal R1525 1.5 hour control brain loop). (c) Deep pits (arrows) were formed in the apical cellular membrane of the FAE (animal R1294 15 minute infected loop). (d) Occasionally, these pits contained vesicles (arrows) (animal R1294 15 minute infected loop). (e, f, g) At two hours post inoculation, MVBs (arrowheads) (e and f) and exosome-like vesicles in intercellular lacunae (arrows) (e and g) were frequent (animal R1292 2 hour sucrose loop). Fig. 2a to e: Bar, 1 µm, Fig f and g: Bar, 0.5 µm.