Real-Time Quantitative RT-PCR
Cells were harvested and restimulated in the presence of immobilized anti-CD3 (2 mug/ml) plus anti-CD28 (2 mug/ml) for 3 hr or immediately lysed. RNA was extracted and reverse-transcribed and cDNA was analyzed for the expression of cytokines and transcription factors by real-time PCR assay as before (Shoemaker etal., 2006). Target gene mRNA expression was quantified either with SYBR Green (Applied Biosystems) or with Master Mix (Applied Biosystems) and normalized to ubiquitin or HPRT mRNA levels, respectively. 
