Representative standard curves for TNFa and SOCS3 mRNAs using the LightCycler device. RNA was isolated using spleen cell cultures stimulated with LPS. The primer sets are listed in Tables 1, 2 and amplification conditions are described in "methods". Slopes and statistical value are assessed using LightCycler 3 software. Data are means ± SEM. A) Variation of standard curve for TNFa mRNA quantification according to mRNA extraction: (blue diamond) anion exchange resin RNA extraction (RNeasy mini, QIAGEN), (red diamond) phenol extraction . Each value is the average of four (phenol) or three (RNeasy) independent mRNA quantifications. Only a weak difference is observed in PCR efficiencies between the templates (-3.398 and -3.399). The CT variation is probably due to the difference in mRNA purity between both extraction methods. B) Intra-assay variation for SOCS3 mRNA quantification. Each value is the mean of three repetitions in the same experiment.