Figure 2

Stability Properties of EK ₂₁₁ , H-type, and Cattle-Passaged TSEs. (A). Classical vs. E211K BSE Stability. Closed circles—Classical BSE (Animal #26); Open circles—E211K BSE. Curves represent the average of 3 technical replicates for each animal, completed using the intermediate method; error bars represent standard deviation of replicates. The experiment was also completed independently using the buffered method, with the same stability pattern observed for the pair of samples (data not shown). Inset: Comparison of stability curves of obex PrP^Sc (closed circles) and cerebellar PrP^Sc (open circles) from the EK₂₁₁ animal (#25). (B). Detailed comparison of classical and H-type stability. Data was collected with the intermediate method and an increased number of data points were taken between 0.25 M and 5 M GdnHCl. Error bars represent SEM and the H-type average curve includes the EK₂₁₁ H-type sample. Inset: As described in the text, the curves in the main panel were normalized to the value at 2 M GdnHCl to display data between 2 and 5 M GdnHCl; closed circles—classical BSE average; open circles—H-type BSE average. Curves for both the main panel and the inset were fit with a 4-parameter logistic function (SigmaPlot). (C). Stability comparison of other TSEs passaged in cattle brain to classical BSE. All curves represent the average of 3 biological replicates (error bars represent SEM), with the exception of the TME (1^st passage in cattle) curve, which displays the average of 2 biological replicates (error bars represent range). Curves were performed with the standard method. Inset: Example of single TME isolate with significantly distorted stability profile, as described in Results. (D). Comparison of classical BSE and bovine scrapie. Curves represent the average of 3 biological replicates (error bars represent SEM), performed using the intermediate method.