In vitro approaches for detection of chemical sensitization.

Concerns, legislation and research needs have precipitated developments such as the mode of action concept, the Tox21 strategy, the concept of pathways of toxicity and the adverse outcome pathway framework. New technologies and paradigms are currently transforming these concepts into applicable animal-free toxicity testing systems. The adverse outcome pathway framework provides a structure for collecting, organizing and evaluating the available data that describe the compound and the events resulting in an adverse outcome at a biological level of organization. The current chapter intends to provide a non-exhaustive review of (i) our current understanding of the molecular mechanisms driven the key events of the mode of action for sensitization induction by chemicals, (ii) the tools that were developed on the basis of the available knowledge and (iii) the major gaps that need to be filled.