Figure 1.
The gp240 antigen is expressed in human melanoma cell lines by FACS analysis. Melanoma cells consisting of 1 x 106 cells were first incubated with mAb ZME-018 IgG2a then stained with APC-conjugated goat anti-mouse antibody, as described under Materials and Methods. As negative staining control, cells were stained with an isotype-matched control antibody of irrelevant specificity (mouse IgG2a). Cells were fixed in 1% paraformaldehyde solution and stored on ice in the dark after washing. FACS analysis was carried out, and APC fluorescence was detected by a FACS Caliber cytometer. For each cell line, 10,000 events were acquired. Analysis was performed with the CellQuest Pro software. Expression of gp240 was indicated as solid lines for all five melanoma cell lines, which were overlaid by dotted lines representing isotype control. High-level expression of the gp240 antigen was demonstrated in all human melanoma cell lines, except TXM-1 cells.