FIG 1.

Endpoint titration of 127S prions by a single round of mb-PMCA. Brain homogenate from tg338 mice infected with 127S prions was serially diluted in tg338 healthy brain lysate as indicated. Each dilution was directly analyzed by Western blotting (a) or served as seed for a single 48-h round of PMCA using different experimental conditions (b and c). Samples were amplified in the absence or presence of 3 ceramic beads (as indicated) in individual PCR tubes or an 8-PCR-tube strip containing 100 µl of PMCA mixtures (b) or in a PCR microplate containing 36 µl of PMCA mixture (c). Unseeded samples (U) were run on the same microplate. All samples were digested with PK before Western blot analysis using Sha31 anti-PrP antibody. Undigested normal brain homogenate (PrP^C) and PK-digested, infected brain homogenate (PrP^res) are provided as electrophoretic references. Molecular mass markers (kDa) are indicated to the left of each panel.