Multiprobe RNase protection analysis of cytokine mRNAs expressed in HTLV-1-infected and uninfected T cells. Total RNA was prepared from the cell lines shown in the right-hand panel. Lanes 1-4: uninfected T-cell lines and activated CD4⁺ and CD8⁺ T cells. Lanes 5-8: chronically infected T-cell lines that do not require IL-2 for growth. Lanes 9-17: HTLV-1-immortalized T-cell lines that require IL-2 for growth. Lane 18: T-cell line immortalized with a lentivirus vector encoding a Tax-YFP fusion protein. Cell surface phenotypes of the IL-2-dependent, HTLV-1-immortalized cells were CD4⁺ (lanes 9-13,18) or CD8⁺ (lanes 14-17). The probes used for RNase protection are shown on the right side of the gel and protected fragments are indicated by arrows on the left side. Probes for L32 and GAPDH mRNA were included as controls for mRNA quantity and quality. The figure shows results from a typical experiment, which was performed at least 3 times.