The COLIPA strategy for the development of in vitro alternatives: Skin sensitisation

Allergic contact dermatitis is a delayed-type hypersensitivity reaction induced by small reactive chemicals (haptens). Currently, the sensitizing potential of chemicals is usually identified on the basis of animal studies, such as the local lymph node assay (LLNA) or guinea pig tests. There are, however, increasing public and political concerns regarding the use of animal testing for the screening of new chemicals. The development of in vitro models for predicting the sensitizing potential of new chemicals is therefore receiving widespread interest and the COLIPA Project Team Skin Tolerance is involved in a range of research projects exploiting our current understanding of the molecular and cellular events occurring during the acquisition of skin sensitization. Projects reflecting many aspects of the complex interactions of a chemical with the different compartments of the immune system are being supported: These approaches range from aspects of chemistry/peptide binding/skin metabolism, through evaluation of intracellular signaling pathways induced by allergens, to allergen induced changes in dendritic/Langerhans cells measured at genomic and protein level. Knowledge gained from this research will be used to support the development and pre-validation of novel in vitro approaches for the identification and characterization of skin sensitizing chemicals.