Fig. 4.

C4 inhibits NF-κB activation. HEK293T cells were transfected with a firefly luciferase reporter plasmid under the control of an (a, b) IFN-β-, (c, d) ISG56.1- or (e, f) NF-κB-dependent promoter, a Renilla luciferase transfection control, and a C4, B14, C6 or GFP expression plasmid or empty vector control (EV). Cells were (a–d) transfected 24 h later with (a, c) poly(dA : dT) or (b, d) poly(I : C) at 800 ng per well for 24 h or (e, f) stimulated directly with (e) IL-1β or (f) TNF-α at 40 ng ml⁻¹ for 8 h and then harvested. Firefly luciferase activity was normalized to Renilla luciferase activity. Data are from one experiment representative of at least three, each performed in triplicate and presented as means±sd. *P<0.05; **P<0.005; ***P<0.0005, compared with EV.