Fig. 10. IL-10 mRNA expression in EBER-transfected cell clones of EBV-negative BL cell lines. EBV-negative Mutu, Louckes, BL41 and BL30 cells were transfected with the EBER plasmid, and cell clones that stably expressed EBERs were selected and analyzed. Cell clones transfected with the neoR gene were used as controls. IL-10 mRNA was quantified by the real-time RT–PCR assay. The results are expressed as the ratio to the value of GAPDH (K × IL-10 copies/5 × 10³ copies GAPDH; K × EBER copies/1 copy GAPDH; K = constant).