TABLE 2.
Time-dependent progression of experimental scrapie infection after intratonsillar inoculation of a scrapie-brain homogenate, by immunohistochemical PrPSc detection in LRS tissues from the 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 | |
| Cranial cervical LN (IPL) | 0/3 | 0/3 | 0/3 | 0/3 | 2 (+++)/1 | 3 (+++)/0 | 3 (+++)/0 |
| Cranial cervical LN (COL) | 0/3 | 0/3 | 0/3 | 0/3 | 2 (+)/1 | 3 (+++)/0 | 3 (++)/0 |
| Mediastinal LN | 0/3 | 0/3 | 0/3 | 0/3 | 2 (++)/1 | 3 (+++)/0 | 3 (++)/0 |
| Prescapular LN (IPL) | 0/3 | 0/3 | 0/3 | 0/3 | 2 (+)/1 | 3 (+++)/0 | 3 (++)/0 |
| Prescapular LN (COL) | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 3 (+++)/0 | 3 (++)/0 |
| Spleen | 0/3 | 0/3 | 0/3 | 0/3 | 2 (+)/1 | 3 (++)/0 | 3 (++)/0 |
| Peyer's patches | 0/3 | 0/3 | 0/3 | 0/3 | 2 (+)/1 | 3 (++)/0 | 3 (++)/0 |
| Mesenteric LN | 0/3 | 0/3 | NA | NA | 2 (+)/1 | 3 (+++)/0 | 3 (+++)/0 |
| Popliteal LN (IPL) | NA | NA | NA | NA | 0/3 | 3 (+)/0 | 3 (++)/0 |
| Popliteal LN (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
LN, lymph node; IPL, ipsilateral; COL, contralateral.