Activation of caspases, but not IL-1β, is involved in the secretion of MIP-1α and MIP-2 in Fas-ligated DCs. DCs were pretreated with different doses of the relatively specific caspase 1 inhibitor Ac-YVAD-fmk (A) or pan-caspase inhibitor ZVAD-fmk (B) for 30 minutes, then stimulated with Jo-2, isotype Ab (Iso), or LPS for 18 hours. The levels of MIP-1α and MIP-2 in supernatants were determined by ELISA. (C) DCs were stimulated with various doses of rmIL-1β for 18 hours. Then the levels of MIP-1α and MIP-2 in the supernatants were determined by ELISA. (D) DCs were pretreated with anti–mIL-1β Ab or isotype Ab (Iso2) for 30 minutes and then treated with Jo-2 for 18 hours, then levels of IL-1β, MIP-1α, and MIP-2 in supernatants were determined by ELISA. The concentration of MIP-1α and MIP-2 shown here was 5-fold diluted. (E) To confirm the effect of the autocrined IL-1β on Fas-induced production of chemokines in DCs, the blocking antibody to mIL-1R type I (mIL-1RI), by which IL-1β transduces its signal, and its isotype antibody, was added to the system. And then concentration of MIP-1α and MIP-2 was detected by ELISA kits.