HEK293T cells were transfected with a firefly luciferase reporter plasmid encoding the IFN-β promoter , plus a TK renilla plasmid and an increasing dose of flag-tagged MARCH2 plasmid (50, 100, 200, 400 ng) plus expression plasmids for RIG-I 2CARD, RIG-I, MDA-5, MAVS or stimulated with poly (I:C), for 24 h. Results are expressed relative to those of renilla luciferase alone (Internal control). 