Tristetraprolin (TTP), ZFP36L1, and ZFP36L2 expression patterns in human monocytes stimulated with lipopolysaccharide (LPS). Purified monocytes from healthy human subjects (n = 5) were stimulated with LPS (or phosphate-buffered saline as control). Total cellular RNA from the monocytes was converted to cDNA and analyzed by real-time polymerase chain reaction for (a) TTP, (b) ZFP36L1, and (c) ZFP36L2 expression levels. Resulting Ct values were normalized to the geometric mean of four internal control transcripts and then to corresponding samples from PBS-treated cultures at the same time points, then converted to 2-ΔΔCt. The normalized values were then expressed as a fraction of the mean value at which maximum expression occurred (t = 1 hour for TTP and ZFP36L2; t = 1.5 hours for ZFP36L1). These were then expressed as means ± s.e.m.