Figure 4.

Inhibited LPS-inducible expression of RANTES and IFN-β in endotoxin-tolerant human monocytes. After prior exposure to medium or 10 ng/ml LPS for 20 h, human monocytes were washed and treated with medium or challenged with 100 ng/ml LPS for 1h (A) or with the indicated concentrations of LPS for 24 h (B). (A): Following stimulation, RNA was isolated, reverse-transcribed and analyzed by real-time PCR with gene-specific primers for RANTES, IFN-β and HPRT. Results of a representative experiment (n=5) are depicted. (B) RANTES secretion levels were assayed in cell-free culture supernatants by ELISA. Shown are data (mean ± sd) of 5 independent experiments. *, P < 0.05; **, P < 0.01.