Enhanced IL-18 production from Wdr1 mutant monocytes in response to TcdB. Wild-type and Wdr1^rd/rd day 3 BMDMs were left untreated or stimulated with 20 ng/ml TcdB for 3 h or 10 µM nigericin (Nig) for 1 h with or without 1 µg/ml LPS. (a and b) Secreted IL-18 (a) or secreted IL-1β (b) in the culture supernatants was measured by ELISA. All data are representative of two independent experiments; error bars represent means ± SEM (n = 3). ***, P < 0.001; ****, P < 0.0001 by unpaired t test.