FIG. 2.
DCs from MyD88−/− mice show impaired S. pyogenes-induced IL-12 responses in vitro. Purified bone marrow-derived DCs from C57BL/6 or MyD88−/− mice were infected in vitro with S. pyogenes for 2 h and further incubated in the presence of antibiotics. (A) IL-12p40 was measured in the supernatant of S. pyogenes-infected (hatched bars) or uninfected (white bars) DCs by ELISA 48 h after infection. DCs stimulated with 2 μg/ml of LPS were used as a control (black bars). Bars show means plus standard deviations (SD) for triplicates. Similar experiments were performed at least three times. (B) RT-PCR amplification of IL-12p40 cDNA from unstimulated, LPS-stimulated, and S. pyogenes-infected DCs isolated from wild-type C57BL/6 (left) or MyD88−/− (right) mice. β-actin expression served as a loading control. Plasmids containing the sequences encoding IL-12p40 or β-actin were used as positive controls (CTR), and reactions in the absence of cDNA were used as negative controls. (C) Changes (x-fold) in the ratio of IL-12p40 mRNA to β-actin mRNA in S. pyogenes-infected or LPS-stimulated DCs compared to those for unstimulated control DCs isolated from either wild-type C57BL/6 mice (black bars) or MyD88−/− mice (white bars).