Quantification of fusion by flow cytometry. (A) CMTMR-stained DCs and CMFDA-stained melanoma (Mel Im) cells were fused using 50% PEG. Three hours after fusion, samples were analyzed by flow cytometry. The percentage of dual-fluorescent cells is indicated for each sample. As controls, cells cocultured for 3 hours without treatment and unstained cells were analyzed. (B) CMTMR-stained DCs and CMFDA-stained melanoma (Mel Im) cells were electrofused using different parameters. A constant current of 50, 62.5 or 100 V per cm was applied to the cells prior to delivery of a pulse of 25 µF - 1000 V/cm. All samples were analyzed as described in 2A. (C) CMTMR-stained DCs and CMFDA-stained primary melanoma cells were electrofused using different parameters as indicated in 2B.