Impact of functional knockdown of TLR signaling on induced cytokine gene expression. Shown are data for the alteration of TNF-α, IL-1A, and IL-6 mRNA concentrations in WT MAC-T cells or those stably transfected with vectors expressing DN-MyD88 and DN-MyD88-DN-TRIF mutants after challenge with heat-inactivated E. coli particles. Mean fold induction values (ordinate, ±SEM) relative to the mRNA concentrations measured in unstimulated MAC-T cells (set as 1) were derived from one experiment representative of three, which was assayed in triplicate. Asterisks indicate that the mRNA concentrations measured for the DN mutant transfectants are statistically different (*, P ≤ 0.05 [by t test]) from those for WT MAC-T cells at the respective time point after E. coli challenge.