To explore the relationship among ER stress, autophagy, and viral replication in FMDV-infection PK-15 cells with 2 MOI, the level of Bip (ER stress marker), LC3-II, and P62 (autophagy marker) were examined by Western blotting at 0, 1, 3, 5, 7, and 9 h postinfection (hpi), respectively. Here, HSPA5 is linked to infection.