Altered Cytokine Export and Apoptosis in Mice Deficient in Interleukin-1β Converting Enzyme

The interleukin-1β (IL-1β) converting enzyme (ICE) processes the inactive IL-1β precursor to the proinflammatory cytokine. Adherent monocytes from mice harboring a disrupted ICE gene (ICE$^{-/-}$) did not export IL-1β or interleukin-1α (IL-1α) after stimulation with lipopolysaccharide. Export of tumor necrosis factor-α and interleukin-6 (IL-6) from these cells was also diminished. Thymocytes from ICE$^{-/-}$ mice were sensitive to apoptosis induced by dexamethasone or ionizing radiation, but were resistant to apoptosis induced by Fas antibody. Despite this defect in apoptosis, ICE$^{-/-}$ mice proceed normally through development.