<i>Bb</i> and its soluble factors dampen TNFα-induced cytokine secretion in epithelial cells.

<p>A. After 4 hour-incubation of HT29-19A cells with TNFα±<i>Bb</i> (MOI 100) or <i>Bb</i>-CM, epithelial cell supernatants were tested by the Raybio® human cytokine array V (One representative array of two experiments). Secretion of chemokines (CXCL1, CXCL8, CCL4) and of other inflammatory molecules was inhibited in the presence of <i>Bb</i> and <i>Bb</i>-CM as judged by densitometric analysis. B. Long lasting inhibition (up to 7 hours) of CXCL8 secretion by <i>Bb</i>-CM (∼50%) was observed using ELISA. n = 7, *<i>p</i><0.01 <i>vs</i> TNFα. C–D. HT29-19A cell monolayers were treated (4 hours) from the basolateral compartment with TNFα together with <i>Bb</i> or commensal bacteria (<i>B.breve</i> ATCC 15698, <i>L.rhamnosus</i> 10863, <i>E.rectale</i> L15) placed in the apical compartment at increasing MOI. As quantified by ELISA, <i>Bb</i> dose-dependently inhibited TNFα-induced CXCL8 secretion, in contrast to other bacteria. n = 11, †<i>p</i><0.0001 ; *<i>p</i><0.001 vs TNFα.