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Description of key information

LLNA
Sensitiser, OECD 429, EU Method B.42 and US EPA OPPTS 870.2600, Latour (2015)

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

The potential for the test material to cause skin sensitisation was investigated in the mouse in a Local Lymph Node Assay (LLNA) carried out in accordance with the standardised guidelines OECD 429, EU Method B.42 and US EPA OPPTS 870.2600 under GLP conditions. The study has been assigned a reliability score of 1 in line with the principles for assessing data quality as defined by Klimisch et al. (1997).

Test material concentrations selected for the main study were based on the results of a pre-screen test. In the main study, three experimental groups of five female CBA/J mice were treated with test material concentrations of 2, 5 or 10 % w/w in acetone/olive oil (4:1 v/v) on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with the vehicle alone.

Three days after the last exposure, all animals were injected with ³H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of disintegrations per minute (DPM) and a stimulation index (SI) was subsequently calculated for each group.

Slight irritation of the ears was shown by three animals treated at 10 % and was considered not to have a toxicologically significant effect on the activity of the nodes.

Most auricular lymph nodes of the animals of the experimental groups were considered enlarged in size. No macroscopic abnormalities of the surrounding area were noted for any of the animals.

Mean DPM/animal values for the experimental groups treated with test material concentrations 2, 5 and 10 % were 12 894, 18 366 and 22 095 DPM, respectively. The mean DPM/animal value for the vehicle control group was 1027 DPM. The SI values calculated for the material concentrations 2, 5 and 10 % were 12.6, 17.9 and 21.5, respectively.

These results show that the test material elicits a SI ≥ 3. The data showed a dose-response and the EC3 value (the estimated test material concentration that will give a SI =3) was established to be between >0 and 2 %.

Under the conditions of this study, the test material is considered to be a sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

In accordance with the criteria for classification as defined in Annex I, Regulation (EC) No 1272/2008, the substance requires classification with respect to skin sensitisation as Category 1A (H317: May cause an allergic skin reaction).

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