Human colon carcinomas constitutively express and shed type II IL-1 receptor, an IL-1 antagonist

We reported earlier that rat intestinal epithelial cells respond to helminth infection, to NSAID injury, and to detachment in vitro with expression of the IL-1RII. Now we have sought to determine whether human colon carcinoma cell lines express, or may be induced to express, this potent IL-1 antagonist. Using RT-PCR, the T84 and HT-29 cell lines constitutively expressed mRNA for the membrane-bound, but not the secreted variant of the receptor. The protein was detectable by immunohistochemistry and was estimated to be 70 kDa by western blotting. TNF treatment of T84 cells led to slightly increased levels of IL-1RII mRNA and to significant increases in soluble protein detected in culture supernatants. Treating T84 cells with inhibitory anti-IL-1RII antibodies led to heightened responsiveness to IL-1, measured as IL-8 production. Expression of the IL-1RII by human epithelial cells has implications in terms of the IL-1 agonist versus antagonist balance in the diseased intestines.