Effect of PL on cytokine production by BMDMs.

<p>BMDMs were pulsed with medium alone, PL at 25/ml, or various TLR ligands; LPS (10 ng/ml) (<b>A</b>), Pam3 Cys4 (Pam3) at 10 ng/ml (<b>B</b>), dsRNA (10 ng/ml) (<b>C</b>), ssRNA (10 ng/ml) (<b>D</b>), CpG DNA (1 µM) (<b>E</b>), or PL before the addition of respective TLR agonists in the medium. Cells were cultured for a total of 24 h period. The cytokine contents of IL-6 and TNF-α in culture supernatants were assayed by using specific sandwich enzyme-linked immunosorbent assays as recommended by the manufacturer (BD biosciences or R&D Systems). Cytokines detected below the assay detection limit for each stimulation are presented as UD (undetected). The mean ± SE concentration of cytokines in five independent experiments was determined. (F) BMDMs were pulsed with medium alone, PL at various concentrations; 5 ug/ml (PL5), 15 ug/ml (PL15) or 30 ug/ml (PL30), before the addition of LPS (10 ng/ml) in the medium. The cytokine contents of IL-6 in culture supernatants were assayed at 24 h as described above. Significant differences were measured by Student's <i>t</i> test and are denoted by asterisks (*, P<0.05, **, P<0.01 and ***, P<0.001).