(A) 293 HEK-TLR3 cells were transfected with 10 ng empty vector, WT, R141X, or ΔNC TRIF along with IFN-β–Luc/NF-κB–Luc and RL-TK vectors to assess induction upon overexpression of TRIF. ΔNC TRIF serves as a dominant-negative construct of TRIF, containg only the TIR domain. Transfected cells were left unstimulated or stimulated with 50 μg/ml poly(I:C) for 4 hours. Firefly luciferase values were normalized using renilla values. Total transfected DNA was held constant by adding empty vector. Values (mean ± SEM) were calculated from 3 independent experiments. (B) Immunoblot analysis of protein lysates from 293HEK-TLR3–transfected cells, using an antibody recognizing the N-terminal of TRIF. CFP was cotransfected as a control for transfection efficiency. Samples were migrated on the same blot. (C) 293HEK-TLR4-MD2-CD14 cells were transfected with 10 ng TRIF vectors, including WT, R141X, and ΔNC TRIF, and the induction of IFN-β–Luc/NF-κB–Luc was assessed by luciferase. Values (mean ± SEM) were calculated from 3 independent experiments. (D) Control (C+) SV40 fibroblasts and P1’s fibroblasts retrovirally transduced with empty vector, WT TRIF, or R141X TRIF were stimulated with 25 μg/ml poly(I:C) for 24 hours, and production of cytokines was assessed by ELISA. Values (mean ± SEM) were calculated from 3 independent experiments. (E) HSV-1 GFP replication was assessed after 24 hours of infection in control SV40 fibroblasts (C+) and SV40 fibroblasts from P1 retrovirally transduced with empty vector, WT, or R141X TRIF. Cells were pretreated with media (left) or recombinant IFN-α (right).Values (mean ± SEM) were calculated from 3 independent experiments.