mRNA expression of cytokine genes by memory CD4/CD80^acq T cells. Memory CD4/CD80^acq T cells were restimulated for 24 hours in the presence of APCs and the indicated concentrations of PCC and separated from APCs, and their RNA was analyzed by RPA. All samples were analyzed with a Th1/Th2 RPA probe set, and band intensity was calculated based on the housekeeping gene L32.