To address the role of NF-κB in mediating the LPS-induced up-regulation of TLR3, we determined the effects of IKK-NBD, an NF-κB inhibitor1920, on LPS-induced TLR3 expression in AMΦ. As shown in Fig. 3B,C, IKK-NBD (100 μM) prevented the LPS-induced up-regulation of TLR3 mRNA and protein expression in AMΦ isolated from WT mice. We observed similar results by quantitative PCR (Fig. 3D). These results demonstrate that NF-κB signaling plays a role in mediating TLR4-TLR3 cross talk.