FIGURE 2.
S. flexneri 2a LPS shows less activity than E. coli K235 LPS in the TLR4-mediated activation of NF-κB. Two × 105 cells/well HEK293T cells were co-transfected with untagged wild-type TLR4 (300 ng/well), huCD14 (30 ng/well) and huMD-2 (3 ng/well), along with the reporter constructs to obtain optimal E. coli LPS-induced activation. After overnight recovery, transfected cells were treated with the indicated concentrations of either E. coli K235 LPS or S. flexneri 2a LPS for 5 hr. Cells were washed twice with cold 1× PBS, lysed in 1× lysis buffer, and centrifuged to remove cell debris. Luciferase and β-galactosidase activities were measured in cell lysates as described in the Methods. A representative experiment is shown (n = 6). * p < 0.05 vs. E. coli LPS at the same concentration.