RT-PCR analysis of IFN-γR2 chain in malignant T cells. ST4 cells were cultured in complete medium (lane 1), in medium without serum (lane 2), in medium without serum supplemented with 100 ng/mL IGF-1 (lane 3), or in complete medium in the presence of 10 μg/mL anti–IGF-1R blocking mAb (lane 4). After 24 hours, cells were recovered and IFN-γR2 and G3PDH (housekeeping gene) mRNA were evaluated. Lane M indicates marker; lane N, contamination control reaction containing all PCR reagents but no substrate cDNA. The size of the PCR fragments is shown on the right.