Figure 3.

Neutral effect of the four finalist dyes over a wide concentration range. PBMC of a CEF-7 reactive donor were tested in an IFN-γ ELISPOT assay for CEF-7—induced production of the cytokine vs. spot formation in the medium control. The test was done in the absence of added dye (0% dye concentration), or in the presence of the specified concentrations of dyes C, D, E, and L, distinguished by colors. (The grey line is dye C, dye E is in yellow, dye D is orange, and dye L is represented by the blue line.) SFU counts in all medium control wells—in the presence or absence of dye—were less than 10/well and are seen as the black symbols overlaying the X axis. The data shown have been obtained from a single donor, and is representative of three additional donors tested.