IFIT3 and infection: In conclusion, the effects of the HP-PRRSV infection on the expression of IFIT3 and IFIT5 in porcine pulmonary MVECs are distinct at different infection stages, IFIT3 and IFIT5 play an important role in inhibiting the HP-PRRSV replication, and APS suppress the multiplication of HP-PRRSV by upregulating their expression.