Twenty-four atypical scrapie cases from sheep with different prion protein genotypes from Great Britain were transmitted to transgenic tg338 and/or TgshpXI mice expressing sheep PrP alleles, but failed to transmit to wild-type mice. Mean incubation periods were 200-300 days in tg338 mice and 300-500 days in TgshpXI mice. Survival times in C57BL/6 and VM/Dk mice were >700 days. Western blot analysis of mouse brain samples revealed similar multi-band, protease-resistant prion protein (PrP(res)) profiles, including an unglycosylated band at approximately 8-11 kDa, which was shown by antibody mapping to correspond to the approximately 93-148 aa portion of the PrP molecule. In transgenic mice, the incubation periods, Western blot PrP(res) profiles, brain lesion profiles and abnormal PrP (PrP(Sc)) distribution patterns produced by the Great Britain atypical scrapie isolates were similar and compatible with the biological characteristics of other European atypical scrapie or Nor98 cases.