TABLE 1.
Time-dependent progression of experimental scrapie infection after intratonsillar inoculation of a scrapie-brain homogenate, by immunohistochemical PrPSc detection in LRS tissues from the heads of lambs under study at different days and months p.i.a
| Organ (body side)b | PrPSc-positive sheep/PrPSc-negative sheep at various times p.i. |
||||||
|---|---|---|---|---|---|---|---|
| 7 days | 1 mo | 3 mo | 5 mo | 7 mo | 9 mo | 12 mo | |
| Palatine tonsil (IPL) | 0/3 | 0/3 | 2 (++)/1 | 2 (+)/1 | 2 (++)/1 | 3 (+++)/0 | 3 (+++)/0 |
| Palatine tonsil (COL) | 0/3 | 0/3 | 0/3 | 1 (+)/2 | 2 (++)/1 | 3 (+++)/0 | 3 (+++)/0 |
| RPLN (IPL) | 0/3 | 0/3 | 3 (+++)/0 | 3 (+++)/0 | 2 (+++)/1 | 3 (+++)/0 | 3 (+++)/0 |
| RPLN (COL) | 0/3 | 0/3 | 0/3 | 2 (+)/1 | 2 (+++)/1 | 3 (+++)/0 | 3 (+++)/0 |
| Third eyelid (IPL) | NA | NA | NA | NA | 2 (+)/1 | 2 (++)/1 | 3 (++)/0 |
| Third eyelid (COL) | NA | NA | NA | NA | 0/3 | 3 (++)/0 | NA |
| SML (IPL) | NA | NA | NA | NA | 0/3 | 3 (++)/0 | 3 (++)/0 |
| SML (COL) | NA | NA | NA | NA | 0/3 | 3 (++)/0 | 3 (++)/0 |
a
All animals were clinically healthy. The intensity of PrPSc immunolabeling is indicated as 1 (+), 2 (++), and 3 (+++). NA, not available.
b
IPL, ipsilateral; COL, contralateral; RPLN, retropharyngeal lymph node; SML, submandibular lymph node.