Serum cytokine levels in SCID mice receiving daily injections of IL-18 plus IL-12.

(A) Four- to 6-week-old female SCID mice received daily injections of IL-12 (1 μg), IL-18 (0.5 μg/d), or IL-18 plus IL-12. Serum was obtained from cytokine-treated mice at the indicated times and analyzed for the presence of muIFN-γ. (B) Serum levels of muTNF-α were measured by ELISA in SCID mice receiving daily injections of IL-18 plus IL-12. (C) Serum levels of muGM-CSF were measured by ELISA in SCID mice receiving daily injections of IL-18 plus IL-12. (D) SCID mice received daily IP injections of IL-18 plus IL-12. Serum was obtained from cytokine-treated mice at the indicated times and analyzed for the presence of IL-1β, IL-6, and IL-10 by ELISA. Mice receiving IL-18 plus IL-12 survived from 3 to 5 days. These results are representative of 3 separate experiments and represent the mean ± SEM of duplicate wells.