FIG. 2.
Hamster nasal cavity with the different types of covering epithelia and the NALT in the lamina propria in the floor of the nasal cavity. (A) A low-power view of a hematoxylin-and-eosin-stained coronal section of half of the nasal cavity from a hamster shows the midline nasal septum, the position of the NALT (indicated by arrows), the boundary between the olfactory and respiratory epithelia (dotted line), and the extent of the follicle-associated epithelium overlying the NALT (asterisks). The olfactory epithelium lines the nasal cavity above the dotted line, while respiratory epithelium lines most of the nasal cavity below the dotted line. The follicle-associated epithelium lines a small part of the nasal cavity that overlies the NALT. Adjacent tissue sections from the areas indicated by boxes 1 to 3 in panel A from a hamster 6 weeks after e.n. inoculation were processed for PrPd using IHC and shown at higher magnifications in panels B to D, respectively. Note the lack of PrPd in the olfactory epithelium (B) and the respiratory epithelium (C) and the adjacent nerve fascicles in the lamina propria (arrows). (D) Punctate deposits of PrPd were identified only in the NALT of hamsters inoculated with HY TME e.n. and not in any other structures. (E) Hematoxylin and eosin staining of hamster NALT, view enlarged from the tissue section in panel A, reveals the morphology of the hamster NALT, which is made up largely of lymphoid tissue. OE, olfactory epithelium; RE, respiratory epithelium; FAE, follicle-associated epithelium. Bars: A, 500 μm; B, C, D, and E, 50 μm.