Figure 3. PMCA analysis of deidentified plasma samples from macaques infected with macaque-adapted vCJD and control macaques. Plasma samples from 2 infected (M1 and M3) and 28 control macaques were sarkosyl precipitated and analyzed by 4 rounds of PMCA. This panel of samples included 6 plasma samples collected at the final bleed (M1, #16, #75, #76; M3, #66, #93, #94), 6 plasma samples collected 1 month before disease onset (M1, #72, #84, #92; M3, #3, #61, #87), and 81 plasma samples from control macaques (93 samples total). Tubes with samples #4, #6, and #19 were partially or totally open upon arrival and were not analyzed. Dilutions of vCJD BH of 10−5 and 10−9 were used as a positive control; the negative control was the unseeded reaction. After completion of the 4 rounds of PMCA, samples from the third and fourth rounds were digested with 50 μg/mL of proteinase K and then analyzed by Western blot. N refers to transgenic mouse normal BH without proteinase K treatment used as a migration control. BH, brain homogenate; PMCA, protein misfolding cyclic amplification; vCJD, variant Creutzfeldt-Jakob disease.