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Temporal stability of local lymph node assay responses to hexyl cinnamic aldehyde
R J Dearman1, J Hilton, P Evans
1Zeneca Central Toxicology Laboratory, Macclesfield, Cheshire, UK.
Journal of Applied Toxicology : JAT
|August 27, 1998
Summary
The local lymph node assay reliably identifies skin sensitization potential over time. Repeated testing with hexyl cinnamic aldehyde showed consistent results, demonstrating the assay
Area of Science:
- Toxicology
- Immunology
- Dermatology
Background:
- The local lymph node assay (LLNA) is a key method for identifying skin sensitization.
- Assay activity is based on lymph node cell proliferation after chemical exposure.
- Previous evaluations did not formally assess the assay's long-term response stability.
Purpose of the Study:
- To investigate the temporal stability of responses in the local lymph node assay.
- To assess if the LLNA provides consistent results over an extended period.
Main Methods:
- Evaluated responses to hexyl cinnamic aldehyde (HCA) in five separate LLNA experiments.
- Experiments were conducted in a single laboratory over a 10-month period.
- Calculated EC3 values (concentration to induce a stimulation index of 3) for each experiment.
Main Results:
- Hexyl cinnamic aldehyde consistently elicited positive responses in all five experiments.
- Minor inter-experimental variation was observed but was attributed to one outlier experiment.
- Excluding the outlier experiment removed significant variations.
- EC3 values derived from each experiment were similar, indicating consistent potency estimation.
Conclusions:
- The local lymph node assay demonstrates relative stability over time.
- The LLNA is a reliable method for assessing skin sensitization potential consistently.
- Findings support the use of LLNA for long-term chemical safety evaluations.