Encephalomyocarditis Virus (EMCV; ATCC, VR-1762) and Vesicular stomatitis virus (VSV, Indiana; ATCC, VR-1415) were amplified in Vero cells (African green monkey kidney cell line; ATCC, CCL-81) and 293T cells, respectively, and stored at -80°C until use. After three cycles of freeze-thawing to release intracellular virus, the supernatant was collected by spinning and used in plaque-forming assays.