Cell culture systems represent a crucial part in basic
prion research; yet, cell lines that are susceptible to
prions, especially to field isolated
prions that were not adapted to rodents, are very rare. The purpose of this study was to identify and characterize a cell line that was susceptible to ruminant-derived
prions and to establish a stable
prion infection within it. Based on species and tissue of origin as well as PrP expression rate, we pre-selected a total of 33 cell lines that were then challenged with natural and with mouse propagated BSE or
scrapie inocula. Here, we report the successful
infection of a non-transgenic bovine cell line, a sub-line of the bovine kidney cell line MDBK, with natural sheep
scrapie prions. This cell line retained the
scrapie infection for more than 200 passages. Selective cloning resulted in cell populations with increased accumulation of PrPres, although this treatment was not mandatory for retaining the
infection. The
infection remained stable, even under suboptimal culture conditions. The resulting infectivity of the cells was confirmed by mouse bioassay (Tgbov mice, Tgshp mice). We believe that PES cells used together with other
prion permissive cell lines will prove a valuable tool for ongoing efforts to understand and defeat
prions and
prion diseases.