An Ex Vivo Brain Slice Culture Model of Chronic Wasting Disease: Implications for Disease Pathogenesis and Therapeutic Development.

Chronic wasting disease (CWD) is a rapidly spreading prion disease of cervids, yet antemortem diagnosis, treatment, and control remain elusive. We recently developed an organotypic slice culture assay for sensitive detection of scrapie prions using ultrasensitive prion seeding. However, this model was not established for CWD prions due to their strong transmission barrier from deer (Odocoileus spp) to standard laboratory mice (Mus musculus). Therefore, we developed and characterized the ex vivo brain slice culture model for CWD, using a transgenic mouse model (Tg12) that expresses the elk (Cervus canadensis) prion protein gene (PRNP). We tested for CWD infectivity in cultured slices using sensitive seeding assays such as real-time quaking-induced conversion (RT-QuIC) and protein misfolding cyclic amplification (PMCA). Slice cultures from Tg12, but not from prnp ^-/- mice, tested positive for CWD. Slice-generated CWD prions transmitted efficiently to Tg12 mice. Furthermore, we determined the activity of anti-prion compounds and optimized a screening protocol for the infectivity of biological samples in this CWD slice culture model. Our results demonstrate that this integrated brain slice model of CWD enables the study of pathogenic mechanisms with translational implications for controlling CWD.