HOIL-1L is required for lethal inflammation upon LPS challenge in vivo. (a) Survival curve for WT or HOIL-1L^−/− mice challenged with 30 mg/kg LPS (n = 10, combined from three independent experiments). (b) Apoptotic marker Annexin-V (red) and hematoxylin-eosin (H&E)–stained spleen sections from mice in a, sacrificed 24 h after LPS injection. Images are representative of three analyzed mice for each condition. Bar, 100 µm. (c) Weight curve of mice from a. (d) Serum IL-1β levels from WT and HOIL-1L^−/− mice sacrificed 24 h after LPS injection were determined by ELISA (n = 4, combined from 2 independent experiments). Data are presented as the mean ± SEM. *, P < 0.0001 by a Log-rank Mantel-Cox test; **, P = 0.0015; ***, P < 0.008 by a Student’s t test.