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. 2015 Jan 21;89(7):3939–3946. doi: 10.1128/JVI.03183-14

FIG 3.

FIG 3

Transmission properties in secondary passage of the atypical CJD case. (A) Transmissibility to the PrP-humanized knock-in mice in the secondary passage of case 2. The brain homogenates of the affected mice in the primary passage were inoculated into additional knock-in mice of each genotype to examine the effects of serial passage on the transmission properties. Transmissibility to each mouse line was identical to that in the primary passage. The codon 129 genotype of mice in the primary passage did not affect the transmissibility in the secondary passage. The mean incubation periods from intracerebral inoculation to the onset of disease and attack rates (number of mice positive for PrP accumulation in immunohistochemical analysis/number of inoculated mice) were as follows: 129M/M-passaged case 2 in 129M/M, 646 ± 10 days (10/10); 129M/M-passaged case 2 in 129M/V, 691 ± 16 days (7/7); 129M/M-passaged case 2 in 129V/V, 285 ± 8 days (8/8); 129M/V-passaged case 2 in 129M/M, 687 ± 43 days (9/9); 129M/V-passaged case 2 in 129M/V, 686 ± 28 days (7/8); 129M/V-passaged case 2 in 129V/V, 328 ± 6 days (9/9); 129V/V-passaged case 2 in 129M/M, 683 ± 57 days (6/7); 129V/V-passaged case 2 in 129M/V, 674 ± 6 days (7/9); and 129V/V-passaged case 2 in 129V/V, 292 ± 9 days (9/9). (B) Neuropathological features in the secondary passage of case 2. Immunohistochemical analysis of PrP in the brains revealed that the 129M/M mice showed widespread PrP plaques in the cerebral cortices, whereas the 129V/V mice showed PrP plaques in the white matter (arrowheads) similar to those in the primary passage. The codon 129 genotype of mice in the primary passage did not affect the neuropathological features in the secondary passage. Scale bar, 100 μm. (C) Biochemical features in secondary passage of case 2. Western blot analysis of PrPSc in the brains using the conventional 3F4 anti-PrP antibody, type 1/type i PrPSc-specific T1 antibody, or type 2 PrPSc-specific T2 antibody revealed that the biochemical characteristics in each mouse line were identical to those in the primary passage. The codon 129 genotype of mice in the primary passage did not affect the biochemical features in the secondary passage. 129M/M-passaged, 129M/M mouse-passaged case 2; 129M/V-passaged, 129M/V mouse-passaged case 2; 129V/V-passaged, 129V/V mouse-passaged case 2.