Figure 1.

Brain homogenates from tg338 mice infected with LA21K (A); 127S (B); LA19K (C); Nor98 (D) and sheep BSE (E) were solubilized and fractionated by sedimentation velocity. Fractions collected from the gradient were analysed for PK-resistant PrP^Sc content (black line) and for infectivity (red line). For each fraction, the percentage of total PK-resistant PrP^Sc detected on the immunoblot is presented (left axis). For each fraction of each strain, infectivity was determined by measuring mean survival times in reporter tg338 mice (mean ± SEM; right, red axis). The sedimentation peaks of standard molecular mass markers (MM markers) are indicated on the top of the graph. From [71].