RT-PCR analysis of IL-15 and control GAPDH, with expression in myeloma cell lines.
(A) RT-PCR analysis of expression of IL-15 (upper) and control GAPDH (lower) in myeloma cell lines. All myeloma cell lines expressed the mRNA of IL-15 (357 bp). Lane 1: PBMC from a healthy donor as positive control; lane 2: erythrocytes from a healthy donor as negative control; lane 3: dH2O as technical negative control; lane 4: RPMI 8226; lane 5: OPM-2; lane 6: MC-Car; lane 7: LP-1; lane 8: IM-9; lane 9: ARH-77; and lane 10: the molecular weight marker pGEM (Promega). (B) Expression of intracellular IL-15 protein in myeloma cell lines and in the plasma cell fraction of myeloma patients. Cells were stained with a specific anti–IL-15 mAb (solid line) or the respective isotype-matched control mAb (dashed line), and FI were determined by flow cytometry. Representative histograms of the cell lines for 1 of 3 independent measurements are presented. Staining profiles representative for IL-15 protein-negative (Pat. #4) and for IL-15 protein-positive primary myeloma cells (Pat. #13) are shown.
