Stability properties of PrPScfrom cattle with experimental transmissible spongiform encephalopathies: use of a rapid whole homogenate, protease-free assay

Table 2 Comparison of [GdnHCl] _1/2 values for isolates under each experimental condition

Experimental conditions	TSE isolate in cattle	Average [GdnHCl]_1/2
Standard	Classical BSE	2.9 ± 0.04 M
Standard	L-type BSE	2.9 ± 0.05 M
Standard	TME (Cattle-passaged)	2.9 ± 0.03 M
Standard	CWD	3.0 ± 0.04 M
Standard	Scrapie	3.3 ± 0.04 M
Buffered	Classical BSE	3.2 ± 0.02 M
Buffered	H-type BSE	3.4 ± 0.03 M
Intermediate	Classical BSE	2.9 ± 0.1 M
Intermediate	H-type BSE (including E211K isolate)	3.5 ± 0.1 M

[GdnHCl]_1/2 values are expressed as the average of data from 3 or more independent animals infected with each TSE type ± the standard error of the mean, with the exception of the E211K BSE case, for which only one animal sample is in existence worldwide. Experimental conditions refer to the buffer system used and are described in detail in the Methods. The intermediate method [GdnHCl]_1/2 values described here do not include the classical vs. scrapie in cattle comparison conducted separately and displayed in Figure 2D. However, we note that if the biological and technical replicates used in that experiment are aggregated with the classical BSE numbers displayed here, the values for classical BSE and scrapie in cattle brain would be 3.0 ± 0.1 and 3.6 ± 0.1, respectively. The H-type BSE [GdnHCl]_1/2 value would remain significantly different from the classical BSE [GdnHCl]_1/2 at p < 0.05, and the scrapie in cattle [GdnHCl]_1/2 value would then be significantly different from the classical BSE [GdnHCl]_1/2 at p < 0.05.

ISSN: 1746-6148