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. Author manuscript; available in PMC: 2008 Feb 12.
Published in final edited form as: Cancer Res. 1999 Jan 1;59(1):59–62.

Fig. 1.

Fig. 1

Melanoma cell lines did not express functional FasL. A, expression of Fas (CD95) was confirmed for the targets by flow cytometry. Closed histogram, staining obtained with hamster immunoglobulin control; open histogram, staining obtained with the Jo2 anti-Fas antibody (PharMingen). The lymphoma lines A20 and L1210-Fas (Fas transfectant) expressed Fas. The parental L1210 demonstrated low levels of Fas expression. B, the lysis assay was found to detect apoptosis (12). The killing of L1210-Fas (■) by the FasL+ D11s line was blocked by the caspase inhibitor z-VAD.fmk but not the control z-FA.fmk (25 μm). The low level of lysis of the parental L1210 (□) was not blocked by the caspase inhibitor, suggesting a nonapoptotic mechanism of cell death. In this assay, the melanoma lines 624.38 and 624.28 did not kill either L1210 or L1210-Fas. C and D, a panel of 19 human melanoma lines were tested in this functional assay. Two of six representative assays are shown. Melanoma lines did not lyse any of the targets. Additionally, functional FasL was not detected in the murine melanoma B16 (data not shown). L1210-Fas was found to be more sensitive than A20 as a target in this functional assay and was used as a target in all of the functional assays performed.