Figure 3.

PrP immunoblots on IBNC and BSE cases. Western blot of 5 different IBNC midbrain samples digested with 4 μl (lanes 2,4,6,11, 13) or 0.3 μl/ml (lanes 3,5,7,12,14) of proteinase K. An individual control brain digested with 4 μ (lane 9,) or 0.3 μl/ml (lane10) proteinase K and a control brain (lane 16) and pooled BSE brains (lanes 17) digested with 20 μl/ml of proteinase K are also present. Molecular markers are at lanes 1,8, and 15. In each case 4 μl/ml proteinase K results in complete digestion of PrP. Although residual PrP^c is present in control brain each of the IBNC brains gives a stronger signal and multiple labelled bands when developed with the F99 antibody at 15 minutes exposure.