PRNP and infection: Lastly, since heterologous shedding occurs (Fig. 5), we assessed transgenic mice expressing either ovine PrP (tg338, infected or not with NPU1 prions; Fig. 6f and Supplementary Fig. 10a, b) or bovine PrP (with or without vCJD infection; Fig. 6g and Supplementary Fig. 10c).