Fig. 1

E. histolytica activates caspase-4 and -1 in a dose and time-dependently manner. a, b THP-1 macrophages were incubated with increasing ratios of Eh for 60 min, and monosodium urate crystals (MSU) were added at 300 μg/mL for 6 h as a positive control. Cells only were used as an internal control. Cell supernatant was TCA precipitated and cells were washed and lysed. Equal amounts of lysates were loaded onto SDS-PAGE gel and immunoblotted with the indicated antibodies. b Cell supernatant was added to HEK-Blue™ IL-1β reporter cells to detect bioactive IL-1β using the SEAP assay. c–e THP-1 macrophages were incubated for increasing amounts of time with 1:20 Eh to macrophage ratio. Immunoblot analysis was performed for caspase-4, caspase-1, IL-1β in both the supernatants (SN) and lysates (LYS), and blots were reprobed for GAPDH. d Cell supernatant was added to HEK-Blue™ IL-1β reporter cells to detect bioactive IL-1β using the SEAP assay. e Cell death was measured by lactate dehydrogenase (LDH) release into the culture supernatant and is shown as a percentage of LDH release compared to non-stimulated cells (control). LN is abbreviated for LPS (50 ng/mL) and nigericin (10 μM) stimulation for 60 min. Data are representative of three independent experiments and statistical significance was calculated with an ANOVA and Bonferroni’s post-hoc test (*p < 0.05, ***p < 0.001). Bars represent ± SEM