FIG. 2.

IL-12 is induced by B. abortus and bDNA but not LPS. BALB/c spleen cells were cultured with LPS and bDNA (from B. abortus and E. coli) and with B. abortus. Supernatants were removed at the indicated times and assayed for IL-12 p70 levels by ELISA. Cells cultured with LPS, and untreated cells produced similar constitutive amounts of IL-12 p70, at levels near the detection limits of the ELISA (5 pg/ml). In contrast, bDNA and B. abortus both elicited IL-12 production in excess of the control cultures at early time points. The results of one of three similar experiments are shown.