The acceptance of a more expanded application of a standardized in vitro method for toxicity testing after airborne exposures has improved significantly in recent times (e.g. Draft proposals of OECD testing guideline 403, 436 and Guidance document 39; REACH regulation). The aim of the study was the pre-validation of the ALI technology (Air-Liquid-Interface) towards an in vitro method for investigation of the toxic and genotoxic potential of inhalable substances. For that purpose human lung cell line A-549 were grown on microporous membranes and exposed to air or noxious gases directly. The pre-validation study was carried out on the basis of common standard operating procedures (SOP) by four laboratories: Fraunhofer-ITEM Hannover, BAuA Berlin, BfR-ZEBET Berlin, UFZ Leipzig. A total of four test gases with toxic potency and one test gas which serve as a negative control were investigated using a cytotoxic (electronic cell counting and analysis) and a genotoxic endpoint (Comet assay). Results of the first pre-validation phase demonstrate a good intra- and inter-laboratory reproducibility. The in vitro data correlate with in vivo data from animal experiments (literature data). The number of tested gases was too small to statistically firm a prediction model. Before entering the international validation phase the enlargement of the database will therefore guarantee a secure assessment of this alternative method.
Unit 4.7 "Biological Agents"