LrpCBA pilus-mediated cellular variation of TLR2-regulated NF-κB responses and endogenous IL-8 production in live and heat-treated HEK-TLR2 cells.

<p>Live (-) and heat-treated (+) normalized cultures of <i>L</i>. <i>ruminis</i> cells and the recombinant GRS1224 (WT) and GRS1225 (LrpC-deleted) lactococci (MOI 100) were combined with HEK-TLR2 cells. TLR2-dependent NF-κB activation <b>(A)</b> and endogenous IL-8 production <b>(B)</b> were measured. GRS71 and GRS1052 cells were used as controls and treated similarly. Measurements also taken for DMEM cell-culture medium and a TLR2-agonist lipopeptide (Pam3CSK4; 1 ng/ml) were used as negative and positive controls, respectively. Triplicate measurements were made for both sets of experiments. Limit bars show SEM. Statistical differences for individual pairwise comparisons against the GRS71 control (unheated) are specified as *** = <i>P</i> ≤ 0.001 (highly significant), ** = <i>P</i> ≤ 0.01 (very significant), or <i>ns</i> = <i>P</i> > 0.05 (not significant). Individual pairwise comparisons of data between the heated and unheated samples are indicated as *** = <i>P</i> ≤ 0.001 (highly significant), ** = <i>P</i> ≤ 0.01 (very significant), * = <i>P</i> ≤ 0.05 (significant), or <i>ns</i> = <i>P</i> > 0.05 (not significant).