Additional evidence localizing synergistic effect on inflammation. A, in contrast to the TNF-α-induced increase in phospho-NIK, TNF-α exposure did not increase phospho-IκBα in the NCM460 cells, and there was no synergistic effect between CGN (1 μg/ml) and TNF-α (0.01 ng/ml) for 24 h, consistent with restriction of the synergistic effect of CGN and TNF-α to the non-canonical pathway. B, inhibition by TLR4 blocking antibody of the TLR4 receptor nullified the CGN-induced increase in IL-8 but had no effect on the TNF-α (0.1 ng/ml for 24 h)-induced IL-8 response. Inversely, blocking of TNFR1 receptor by antibody against sTNFR1 abrogated the TNF-α-induced IL-8 response but not the CGN-induced IL-8 response. Error bars, S.D.