Development of the “Cell Chip”: a new in vitro alternative technique for immunotoxicity testing

Predictive testing of immunotoxicity associated with chemical compounds is complicated and cannot be accomplished with a single test. As most of the existing tests for immunotoxicity employ experimental animals, there is an increasing need for alternative tests in vitro. We have developed a new system for in vitro immunotoxicity testing, which employs changes in cytokine expression observed in vitro as an endpoint indicating potential for perturbation of the immune system in vivo. This system named “fluorescent cell chip” (FCC) is based on a number of genetically modified cell lines that regulate the expression of a transgene coding for fluorescent protein enhanced green fluorescent protein (EGFP) in a similar way as they regulate expression of IL-1β, IL-2, IL-4, IFN-γ, IL-10, TNF-α, and β-actin. Morphological and functional features of selected cell lines expressing EGFP under the control of cytokine promotors were compared with maternal cell lines and this comparison showed that critical functional features of the maternal cell lines were preserved in EGFP expressing cells. Two chemicals with known immunotoxic activities, cyclosporine A and potassium tetrachloro-platinate(II), mediated compound-specific pattern of inhibition and activation of reporter gene expression. Thus, the “fluorescent cell chip” has demonstrated potential for application as a predictive screening test for immunomodulatory activities of chemicals. The major advantage of this approach is the possibility to apply this test in high throughput screening of high number of compounds for their well defined biological activity.