Aeby, P. and M. Bracher. Evaluation of CD86 Modulation and IL-1b Gene Expression on Cultured Dendritic-Like Cells as Predictive Endpoints for Contact Sensitisers. 1999. ATLA 27: 359.

In vitro sensitisation assays have been proposed by various research groups and are actively being developed in our laboratories. The test described here is based on in vitro cultured dendritic-like cells (DCs) derived from human peripheral blood mononuclear cells. These cells serve as replacement for Langerhans cells which are the most important antigen presenting cells in the skin. After application of contact allergens to DCs, very rapid and selective increases of IL-1b mRNA expression followed by cell maturation have been reported (for example, Reutter et al. Toxicology in Vitro 11, 619-626, 1997 and Aiba et al. European Journal of Immunology 27, 3031-3038, 1997). In the present work, the cell culture and the reverse transcriptase-polymerase chain reaction (RT-PCR) conditions have been optimized. The expression of IL-1b mRNA has been measured 15 minutes after application of the test substance by a semi-quantitative RT-PCR procedure using some newly developed internal standards. Maturation of the DCs observed as a time-dependent modulation of the CD86 positive cell population was then measured between 4 and 48 hours by flow cytometry. Known irritants and sensitisers, as well as other potential sensitisers, were evaluated in this test format. Our results indicate that exposure to sensitisers but not to irritants induced reproducible increases in the CD86 positive cell population after 24 hours. Specific and discriminating increases in IL-1b mRNA expression could also be observed in many, but not all, experiments.