Expression and molecular characterization of the CD138/syndecan-1 antigen in cells from PEL. (A) Flow cytometry profiles showing CD138/syndecan-1 surface expression in primary tumor cells from patient no. 1, human PEL-derived cell lines (BC1 and BC2), the human myeloma cell line U266, and myeloid leukemia cells KG-1A. Cells were incubated with the anti-CD138/syndecan-1 MoAb BB-4 (solid lines) and an irrelevant isotype-matched mouse antibody (dotted lines), followed by fluorescein isothiocyanate (FITC)-labeled goat antimouse Ig. The X- and Y-axes, respectively, indicate the logarithm of relative green fluorescence intensity and the relative cell numbers. (B) Relative differences in CD138/syndecan-1 surface expression among PEL-derived cell lines (CROAP-2, BCBL-1, BC-1, BC-2, and HBL-6), human myeloma cells U266, and myeloid leukemia cells KG-1A. Fluorescence values were converted into MESF by comparing the results of anti-CD138/syndecan-1 staining with calibrated reference microbeads containing measured numbers of FITC molecules. Results are expressed as the mean ± SEM of net MESF values derived from three different experiments. (C) Western blot analysis of cell lysates from the human myeloma cell line U266 (5.0 × 106/100 μL), the PEL cell line BC-1 (5.0 × 106/100 μL), and the acute myelogenous leukemia cell line KG-1A (2.5 × 106/100 μL). The blot was incubated with 1.5 μg/mL of the anti-CD138/syndecan-1 MoAb BB-4 and shown by chemiluminescence. The position of molecular weight markers is indicated.
