Expression of CD30L in malignant cells from lymphoid tumors as assessed by RT-PCR (A), flow cytometry (B), and Northern blot analysis (C). (A) cDNA bulks were amplified with primer pairs specific for CD30L (upper panel) or β-actin (lower panel). The MN-60 and the BV-173 cell lines were used as positive (+) and negative (−) controls, respectively. (B) Flow cytometry analysis of representative cases of lymphoid malignancies. Cells were either incubated with the anti-CD30L MoAb M80 (bold line) or irrelevant isotype-matched mouse Ig (thin line), followed by PE-labeled goat antimouse Ig. The X- and Y-axes indicate the logarithm of the relative intensity of red fluorescence and relative cell numbers, respectively. (C) Northern blot analysis of the same cases shown in (B). Twenty micrograms of total RNA per lane was run on denaturated agarose gel, blotted onto nylon membranes, and hybridized with a CD30L-specific cDNA probe (upper panel) and with a GAPDH cDNA fragment (lower panel); +, positive control (MN-60 cell line); −, negative control (BV-173 cell line).