LTA1 and dmLT activate the inflammasome in APCs, including expression of caspase-1, pro-IL-1β, and cleaved IL-1β.
(A) Secreted cytokines detected in 24h culture supernatants from THP-1 cells (0.8x106/0.5ml) treated with media alone (untx) or with 1 ug/ml dmLT or 10 ug/ml LTA1. Signifiance tested by ANOVA with Bonferroni post-test for all groups compared to untx and as indicated (**P ≤ 0.01, ***P ≤ 0.001). (B) THP-1 cells were incubated with PMA for 12h and then treated with media alone (untx) or containing positive control 0.5 μg/ml LPS, 1 μg/ml dmLT, 5 or 20 μg/ml LTA1 for 12h. Representative Western blot images of cell lysates stained with anti- pro-IL-1β (band at 31kD), cleaved IL-1β (17kD), actin (42kD), and cleaved caspase-1 (Casp1, 20kD) antibodies. (C) Fold change from untx using relative intensity of protein bands normalized to actin control compiled from 4–6 separate experiments. Bars at mean+SEM.
