Figure 2. Molecular analyses of the zebu under investigation. Western immunoblot with monoclonal antibodies (MAbs) 6H4 (upper panel) and P4 (lower panel) after limited proteinase K digestion (100 μg/mL, 40 min, 48°C) of 10% brainstem (lanes 3 and 4) and thalamus (lanes 5, 6, and 7) tissue homogenates of the zebu (lanes 3 and 5), a cow with bovine spongiform encephalopathy (lanes 4 and 6), and a sheep with scrapie (lane 7). An undigested cattle brainstem tissue homogenate (lane 1) and a cerebrum tissue homogenate of a spongiform-encephalopathy-negative zebu (lane 2) were included as controls. All samples were processed equally as described by Stack et al. (7), and the membranes were exposed in parallel on the same photographic film. Molecular mass standards in kilodaltons are indicated on the right; tissue mass equivalents, at the bottom.