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Table 2 Infectivity measured by PrPSc positivity rates in Tgbov XV mice inoculated with brain homogenates after different treatments

From: Stability of BSE infectivity towards heat treatment even after proteolytic removal of prion protein

Dose No detergent Detergent Detergent; heat Detergent; heat; keratinase
(10log g mL−1) no ppt no ppt ppt no ppt ppt no ppt ppt
−2 9/10 (2) n.d n.d 15/15 (0) 12/13 (2) 14/15 (0) 15/15 (0)
−3 12/13 (0) n.d n.d 5/15 (0) 14/15 (0) 14/16 (0) n.d
−4 10/12 (0) n.d n.d 0/15 (0) 2/13 (2) 4/15 (1) n.d
−5 3/12 (0) 3/15 (0) 10/15 (0) 1/15 (0) n.d 3/16 (0) n.d
−6 1/15 (0) 3/13 (2) 1/14 (1) 0/15 (0) n.d 2/13 (2) n.d
−7 0/15 (0) 2/15 (0) 1/14 (1) 0/15 (0) n.d 1/15 (0) n.d
−8 0/15 (0) 0/14 (1) 1/15 (0)     
−9 0/14 (1) 0/15 (0) 0/15 (0)     
10log ID50 g−1 6.2 6.4** 6.7** 4.6 5.3* 5.7  
  1. Disease rates were estimated as number of animals confirmed positive (based on testing for PrPSc) and the total number of animals that lived longer than 100 days post inoculation. Between parentheses the number of animals per dose group not included for disease validation because of early death i.e. < 100 days post inoculation. These animals were PrPSc negative by Western blotting. Dose was calculated using the percentages per group in the formula of Spearman and Kaerber. N.d.: not done; ppt = precipitated with methanol. Asterisks * and **: for enabling calculations, figures for the n.d. disease rates were borrowed per equal dose group respectively from the columns detergent/heat/no ppt and no detergent/no ppt.