PRKCD and infection: CRFK cells were infected with a mixture of FCoV (MOI of 1) and RL (2.5 μM), and the cell lysates were collected at 15, 30, 45, and 60 min after infection for Western blotting to measure total PKCδ, phosphorylated PKCδ (PKCδ-S645), and β-actin.