Table 1.
Inoculation of atypical scrapie isolates in bovine PrP (tgBov) expressing mice
| Isolates | TgBov | |||||||
| First passage | Second passage | Third passage | ||||||
| Identifiant | Origin | Genotype | Positive mice | Incubation, mean ± SD | Positive mice | Incubation, mean ± SD | Positive mice | Incubation, mean ± SD |
| AS 1 | Fr | ARQ*/ARQ | 1/6 | 533 | 3/5 | 317 ± 63 | 7/7 | 235 ± 16 |
| AS 2 | Sp | ARR/ARQ | 0/6 | >650 | 7/9 | 354 ± 26 | 5/5 | 273 ± 5 |
| AS 3 | Sp | ARQ/ARH | 0/6 | >650 | 2/11 | 504, 525‡ | 12/12 | 269 ± 13 |
| AS 4 | Nor | ARQ*/ARQ* | 3/4 | 395 ± 44 | 6/6 | 230 ± 17 | 6/6 | 271 ± 18 |
| AS 5 | Sp | ARQ/ARQ | 0/6 | >650 | 0/4 | >650 | NA | — |
| AS 6 | Sp | ARQ/ARH | 0/6 | >650 | 1/4 | >650‡ | NA | — |
| AS 7† | It | ARQ/AHQ | 0/6 | >650 | 1/7 | 424 | 6/6 | 286 ± 14 |
| AS 8 | Po | ARQ/ARQ | 1/5 | 439 | 5/5 | 297 ± 14 | 6/6 | 250 ± 4 |
| PS42 | Fr | VRQ/VRQ | 0/6 | >650 | 0/6 | >650 | 0/6 | >650 |
| Ovine c-BSE | Fr | ARQ/ARQ | 6/6 | 254 ± 19 | 6/6 | 234 ± 12 | 6/6 | 232 ± 6 |
| Cattle c-BSE | Fr | — | 6/6 | 295 ± 12 | 6/6 | 265 ± 35 | 6/6 | 243 ± 7 |
Transgenic mice that express the bovine PrP (tgBov) were inoculated intracerebrally (6 to 12 mice, 20 µL per mouse) with 8 sheep or goat (†) atypical scrapie (AS) isolates originating from 5 different countries, France (Fr), Spain (Sp), Norway (Nor), Italy (It) or Portugal (Po). The AS affected animals displayed a different PRNP genotype at codons 136, 154, and 171. Some also displayed a F/L dimorphism at codon 141 (*). Cattle classical BSE (c-BSE), ovine c-BSE (first passage of cattle c-BSE in an ARQ/ARQ sheep by the intracerebral route), and classical scrapie (PS42) isolates were inoculated in the same mouse model. After first and second passages, clinically affected or asymptomatic mice that had lived for more than 500 d post inoculation were pooled and used for subsequent passage in the same line. Mice were considered positive when abnormal PrP deposition was detected in the brain. Incubation periods (in days) are shown as mean ± SD except when less than 50% of the mice were found to be positive. In that case, the incubation periods of the positive mice are individually presented. NA, not available. Cattle c-BSE transmission in tgBov data from ref. 51. PS42 transmission data from ref. 15.
Abnormal PrP positive and found dead animals (without symptoms).