Comparison of blood infectivity titers measured by TgBov mouse bioassay with results of in vitro blood tests
| Sheep ID . | Status . | Time point, mpi . | No. of positive mice/no. of mice inoculated∗ . | Log10 infectivity titer ID50/mL WB (95% CI)† . | Result of testing blinded panels with in vitro assays . | LoD by mb-PMCA‡ . | ||
|---|---|---|---|---|---|---|---|---|
| mb-PMCA . | capture-PMCA . | WB IOME RT-QuIC . | ||||||
| N236 | Donor | 6 | 0/12 | 0 (0-2.5) | + | + | − | 10−1 |
| 10 | 9/12 | 3.5 (3.1-3.9) | + | ND | + | 10−4 | ||
| 12 | 11/12 | 3.5 (3.1-3.9) | ND | ND | ND | 10−4 | ||
| 18/terminal | 8/12 | 3.3 (2.9-3.7) | + | + | + | 10−4 | ||
| N218 | Donor | 6 | 0/12 | 0 (0-2.4) | − | − | − | NA |
| 10 | 0/11 | 0 (0-2.5) | − | ND | − | NA | ||
| 18 | 11/12 | 3.6 (3.2-4.0) | + | + | + | 10−4 | ||
| 25 | 8/12 | 3.0 (2.7-3.4) | ND | ND | ND | 10−4 | ||
| 28/terminal | 0/12 | 0 (0-2.4)§ | + | + | + | 10−4 | ||
| N245 | Donor | 6 | 0/12 | 0 (0-2.4) | +/− | − | − | ND |
| 10 | 9/12 | 2.8 (2.6-3.2) | + | ND | + | 10−2 | ||
| 18 | 12/12 | 3.9 (3.5-4.3) | + | + | + | 10−5 | ||
| 28 | 10/12 | 3.6 (3.2-4.0) | + | + | + | 10−5 | ||
| 32/terminal | 8/12 | 2.8 (2.5-3.1) | + | + | + | 10−4 | ||
| P480 | Recipient | 6 | 11/12 | 3.3 (2.9-3.7) | + | + | + | 10−5 |
| 9 | 11/12 | 3.8 (3.4-4.2) | + | + | + | 10−4 | ||
| 12 | 12/12 | 3.8 (3.4-4.2) | + | + | + | 10−4 | ||
| 16/terminal | 11/12 | 3.4 (3.1-3.8) | + | + | + | 10−3 | ||
| M246 | Recipient | 6 | 10/12 | 2.9 (2.6-3.2) | + | + | + | 10−3 |
| 9 | 9/12 | 3.0 (2.7-3.4) | + | + | + | 10−4 | ||
| 12 | 10/12 | 3.3 (2.9-3.7) | + | + | + | 10−3 | ||
| 15 | 11/11 | 3.2 (2.9-3.6) | ND | ND | ND | 10−4 | ||
| 19/terminal | 5/12 | 2.7 (2.5-3.0) | + | + | + | 10−3 | ||
| M490 | Recipient | 6 | 6/11 | 2.7 (2.4-3.0) | + | + | + | 10−3 |
| 9 | 8/12 | 3.1 (2.8-3.6) | + | + | + | 10−4 | ||
| 15 | 8/12 | 3.0 (2.7-3.3) | ND | ND | ND | 10−3 | ||
| 21 | 6/12 | 2.8 (2.5-3.1) | ND | ND | ND | 10−4 | ||
| 26/terminal | 3/12 | 2.4 (2.0-2.7) | + | + | + | 10−4 | ||
| N239 | Negative control | 6 | 0/12 | 0 (0-2.3) | − | − | − | NA |
| 10 | 0/12 | 0 (0-2.4) | − | ND | − | NA | ||
| 12 | 0/12 | 0 (0-2.3) | ND | ND | ND | NA | ||
| 27 | 0/12 | 0 (0-2.3) | − | − | − | NA | ||
| 34 | 0/12 | 0 (0-2.3) | − | − | − | NA | ||
| Sheep ID . | Status . | Time point, mpi . | No. of positive mice/no. of mice inoculated∗ . | Log10 infectivity titer ID50/mL WB (95% CI)† . | Result of testing blinded panels with in vitro assays . | LoD by mb-PMCA‡ . | ||
|---|---|---|---|---|---|---|---|---|
| mb-PMCA . | capture-PMCA . | WB IOME RT-QuIC . | ||||||
| N236 | Donor | 6 | 0/12 | 0 (0-2.5) | + | + | − | 10−1 |
| 10 | 9/12 | 3.5 (3.1-3.9) | + | ND | + | 10−4 | ||
| 12 | 11/12 | 3.5 (3.1-3.9) | ND | ND | ND | 10−4 | ||
| 18/terminal | 8/12 | 3.3 (2.9-3.7) | + | + | + | 10−4 | ||
| N218 | Donor | 6 | 0/12 | 0 (0-2.4) | − | − | − | NA |
| 10 | 0/11 | 0 (0-2.5) | − | ND | − | NA | ||
| 18 | 11/12 | 3.6 (3.2-4.0) | + | + | + | 10−4 | ||
| 25 | 8/12 | 3.0 (2.7-3.4) | ND | ND | ND | 10−4 | ||
| 28/terminal | 0/12 | 0 (0-2.4)§ | + | + | + | 10−4 | ||
| N245 | Donor | 6 | 0/12 | 0 (0-2.4) | +/− | − | − | ND |
| 10 | 9/12 | 2.8 (2.6-3.2) | + | ND | + | 10−2 | ||
| 18 | 12/12 | 3.9 (3.5-4.3) | + | + | + | 10−5 | ||
| 28 | 10/12 | 3.6 (3.2-4.0) | + | + | + | 10−5 | ||
| 32/terminal | 8/12 | 2.8 (2.5-3.1) | + | + | + | 10−4 | ||
| P480 | Recipient | 6 | 11/12 | 3.3 (2.9-3.7) | + | + | + | 10−5 |
| 9 | 11/12 | 3.8 (3.4-4.2) | + | + | + | 10−4 | ||
| 12 | 12/12 | 3.8 (3.4-4.2) | + | + | + | 10−4 | ||
| 16/terminal | 11/12 | 3.4 (3.1-3.8) | + | + | + | 10−3 | ||
| M246 | Recipient | 6 | 10/12 | 2.9 (2.6-3.2) | + | + | + | 10−3 |
| 9 | 9/12 | 3.0 (2.7-3.4) | + | + | + | 10−4 | ||
| 12 | 10/12 | 3.3 (2.9-3.7) | + | + | + | 10−3 | ||
| 15 | 11/11 | 3.2 (2.9-3.6) | ND | ND | ND | 10−4 | ||
| 19/terminal | 5/12 | 2.7 (2.5-3.0) | + | + | + | 10−3 | ||
| M490 | Recipient | 6 | 6/11 | 2.7 (2.4-3.0) | + | + | + | 10−3 |
| 9 | 8/12 | 3.1 (2.8-3.6) | + | + | + | 10−4 | ||
| 15 | 8/12 | 3.0 (2.7-3.3) | ND | ND | ND | 10−3 | ||
| 21 | 6/12 | 2.8 (2.5-3.1) | ND | ND | ND | 10−4 | ||
| 26/terminal | 3/12 | 2.4 (2.0-2.7) | + | + | + | 10−4 | ||
| N239 | Negative control | 6 | 0/12 | 0 (0-2.3) | − | − | − | NA |
| 10 | 0/12 | 0 (0-2.4) | − | ND | − | NA | ||
| 12 | 0/12 | 0 (0-2.3) | ND | ND | ND | NA | ||
| 27 | 0/12 | 0 (0-2.3) | − | − | − | NA | ||
| 34 | 0/12 | 0 (0-2.3) | − | − | − | NA | ||
CI, confidence interval; NA, not applicable; +, positive; +/−, weak positive; −, negative.
Number of TgBov mice that tested positive/total number of mice inoculated.
Log10 infectivity titer (equivalent to Log10 ID50/mL WB), as determined by intracerebral inoculation in TgBov mice. 95% confidence intervals are shown in parentheses.
LoD determined independently by testing a dilution series of corresponding sample by mb-PMCA.
Terminal blood sample (28 mpi) from donor N218 did not transmit infection to mice, despite testing positive in all 3 in vitro assays, and positive transmissions from samples at earlier time points (18 mpi and 25 mpi); the reason for this apparently anomalous result could not be determined.