Here - Stiftung Forschung 3R

21st Century: A Vision and a Strategy’
(NRC, 2007), Sens-it-iv emphasised the
necessity of physiologically-relevant,
metabolic competent and robust assays.
Furthermore, -omics based strategies
were followed enabling the identification
of key pathways of toxicity.
The concordance of this two-tiered
approach with the LLNA is 79% for potency
ranking and 92% for classification into the
correct potency groups (extreme, strong,
moderate, weak).
2. Lung EC
1. Keratinocytes
Most advanced among the tests for skin
sensitisation is a two-tiered combination
of the keratinocyte assays mentioned
in Table 2 and illustrated in Figure 3.
Intracellular production of IL-18 by a
keratinocyte cell line such as NCTC2544
(tier 1) quantitatively indicates skin
sensitisers (including many pro-haptens)
but not respiratory sensitisers. The
irritation assay (tier 2) of identified
skin sensitisers in epidermal equivalent
cultures (e.g., CEST1000 (CEllSystems),
RHE (SkinEthics) among others) permits
their grading according to potency.
The assays for respiratory sensitisers
include induction of typical activation
markers in reconstituted alveolar
(developed by Iris Hermanns, Mainz
University, Germany) or bronchial
epithelium cultures (MucilAir, Epithelix,
Switserland) as well as human precision
cut lung slices (PCLS) to simulate an in
vivo-like situation. These tests have been
extensively evaluated on both chemicals
and proteins, which provided confidence
in the capacity of these test systems to
identify respiratory sensitisers.
The alveolar and bronchial cell-based
tests are presently further assessed
Figure 3. The two-tiered principle.
References (see also Publication section for detailed references): Spiekstra SW, et al. Toxicol In Vitro. 2009; 23,
349-55; Corsini E et al. Toxicol. In Vitro. 2009; 23, 789-96.
PROGRESS REPORTS FROM EU-FUNDED PROJECTS
Progress Report 2011 & AXLR8-2 Workshop Report
167