FIG. 6.

Induction of IL-12 by CT and IFN-γ. Alveolar macrophages were cultured for 12 h in complete medium alone and then were cultured with the indicated treatments for 36 h. Samples were assayed for IL-12 bioactivity by lymphoblast proliferation assay. bCT, boiled CT. (A) Proliferation of lymphoblasts treated with culture supernatants that were preincubated with (hatched bars) or without (solid bars) an IL-12-neutralizing antibody. (B) IL-12 bioactivity determined from a standard curve generated with porcine IL-12.