TRANSMISSION OF THE BSE AGENT TO MICE IN THE ABSENCE OF DETECTABLE ABNORMAL PRION PROTEIN

The agent responsible for transmissible spongiform encephalopathies (T SEs) is thought to be a malfolded, protease-resistant version (PrPres) of the normal cellular prion protein (PrP). The interspecies transmis sion of bovine spongiform encephalopathy (BSE) to mice was studied. Al though all of the mice injected with homogenate from BSE-infected catt le brain exhibited neurological symptoms and neuronal death, more than 55 percent had no detectable PrPres. During serial passage, PrPres ap peared after the agent became adapted to the new host. Thus, PrPres ma y be involved in species adaptation, but a further unidentified agent may actually transmit BSE.