Figure 4. Verification of infectivity in PES cells by mouse bioassay.

A) Cell lysates of PESSc cells were inoculated into three groups of mice (six animals each group): Tgbov XV, Tgshp IX and C57/BL6. Tgbov XV mice succumbed to disease 245 ± 29 dpi, Tgshp IX mice died 444 ± 23 dpi and the first non-transgenic mouse was culled due to clinical signs 472 days post inoculation. The brain homogenates were tested by western-blot analysis for PrP^res signals. B) Side by side western-blot analysis of PK digested PrP^res derived from PESSc cells shows a higher molecular weight than PK digested PrP^res from PESSc infected Tgbov XV or Tgshp IX mice. C) PES cells were inoculated with brain homogenate from Tgbov XV mouse 1. The cells were split 15 times at a ratio of 1:2 and were then assayed for PrP^res by dot-blot analysis. Uninfected PES cells were assayed as control Ø. mAB: ICSM18.