Respiratory toxicology and immunotoxicology in human precision cut lung slices (PCLS)

Occupational asthma is one of the most common lung diseases in developed countries. Risk assessment for potentially sensitising chemicals is performed in animal models. With an increasing public demand to limit the number of animals used in respiratory research and to reduce the distress to the animals, several models have been developed. Human PCLS are an ex vivo model where all relevant cell types are present in their natural position. We use PCLS to test for modifications of local immune responses assessing a variety of immunological endpoints. Human PCLS were prepared from lung lobes of cancer patients. Tissue was exposed to LPS, dexamethasone, respiratory and contact allergens. Viability of PCLS was determined with WST-1, LDH and LIVE/DEAD staining for confocal microscopy. Cytokine contents were detected with Luminex technology and ELISA. Employing LPS and dexamethasone we were able to show that the inflammatory response in PCLS resemble the in vivo situation very closely. Repeated stimulation with LPS (intra- and inter-assay variances <20%) showed that human PCLS might also be suitable to characterize respiratory irritation and inflammation induced by chemicals. PCLS were exposed to 20 chemicals and IC50 were calculated. We currently investigate cytokine patterns (e.g. IL-1, TNF, IL-8) for the differentiation between respiratory and contact allergens. Indeed, IL-8 production is increased after stimulation with TMA whereas DNCB failed to induce the release of IL-8 to the same extent. It suggests that the combination of cytokine production with cytotoxic data may represent a promising in vitro model for the screening of allergens.