FIG. 1.

IL-12 production by bone marrow-derived macrophages and dendritic cells. Bone marrow-derived macrophages (A) or bone marrow-derived dendritic cells (B) were infected in vitro with promastigotes (L. major - P) or amastigotes (L. major - A) of L. major or promastigotes of L. amazonensis (L. amazon - P) or were stimulated with CD40L-transfected L cells (L-CD40L, striped bars) or LPS (solid bars). Stimulated macrophages were cultivated for an additional 6 or 24 h to measure cytokine mRNA or protein, respectively. Protein levels were determined by ELISA specific for IL-12 p70 on cells which were primed with 100 U of IFN-γ per ml. Determinations were performed in triplicate, and values are expressed as means ± standard deviations. (A, inset) IL-12 mRNA levels were determined by semiquantitative competitive RT-PCR. These experiments are representative of three or more independent determinations.