Semiquantitative RT-PCR analysis of γ-chain mRNA expression in cell lines. Increasing amounts of total input RNA (10, 25, and 50 ng) from transfected CHO cell lines (γ153C-8 and -14, γ153R-24, and γ153A-10) were reverse transcribed and amplified for 25 cycles. The PCR products for the γ-chain (492 bp) and GAPDH primers (452 bp) were visualized by ethidium bromide staining with 2% agarose gels. The samples in the figure were (1) ABβ CHO cells, (2) γ153C-14, (3) γ153C-8, (4) γ153R-24, and (5) γ153A-10.