The production of IL-1β in <i>S</i>. <i>pneumoniae</i>-infected human lung tissue is dependent on PLY and caspase-1.

<p>(A-E) Human lung tissue was infected with 1x10⁶ CFU/mL <i>S</i>. <i>pneumoniae</i> serotype 2 D39 or D39Δ<i>ply</i> and treated with 100 ng/ml Z-YVAD 1 hour before infection where indicated. After 24 h, production of IL-1β (A, B, E) was quantified by ELISA, relative expression of <i>Il1b</i> was determined by qRT-PCR (C), or expression of pro-IL-1β was assessed by immunoblotting (D). Data are shown as mean ± SEM of three (A), five (E) or six (B, C) independent experiments carried out in duplicates. (D) One representative of four independent experiments is shown. Significance is indicated by asterisks ** = p<0.01, *** = p<0.001.