RT-PCR detection of IL-6 and IL-10 mRNA in spleens of Tat-transgenic mice. Whole-cell RNA from the spleens of age-matched control and β-actin–Tat-transgenic mice was reverse transcribed and subjected to PCR using primers specific for IL-6 mRNA (A through C), IL-10 mRNA (D through F), and GAPDH mRNA (internal control; A through F). RT-PCR was performed with 1 μg of input RNA (A and D), 2 μg (B and E), and 5 μg (C and F). PCR products were size-separated and visualized by staining with ethidium bromide. Stained gels were photographed and the PCR products quantitated by scanning with a laser densitometer. M, 100-bp ladder. The areas of the IL-6 (A through C), IL-10 (D through F), and GAPDH (control) peaks are plotted against PCR cycle number. IL-6 Tat, measurement of IL-6 mRNA in Tat-transgenic mice. IL-6 Con, measurement of IL-6 mRNA in control mice. IL-10 Tat, measurement of IL-10 mRNA in Tat-transgenic mice. IL-10 Con, measurement of IL-10 mRNA in control mice. Open circles, GAPDH in Tat-transgenic mice; Open squares, GAPDH in control mice; The analyses of IL-6, IL-10, and GAPDH were performed at the same time on the same splenic RNA samples. The analyses shown in (A) and (B) were performed on Tat-transgenic line 29. Parallel experiments conducted on line 21 yielded similar results.