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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012
Reliability:
1 (reliable without restriction)
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Remarks:
; measuring the cell counts instead of radioactive labeling
Principles of method if other than guideline:
A modification of the assay by measuring the cell counts instead of radioactive labeling provides comparable sensitivity, and has the advantage that the cell suspension can be further analyzed by different methods (flow cytometry, chemiluminescence responses, immunofluorescence) to gain an insight into mechanistic events. A further modification was done by including the measurement of the ear swelling after treatment leading to a much more simplified and reliable assay (Integrated Model for the Differentiation of Skin reactions (IMDS). By comparing the specific immune reaction induced by the test item in the draining lymph nodes (LN cell counts / LN weights) with the immediate unspecific acute skin reaction (ear swelling / ear weight) it is possible to discriminate the irritant potential from the sensitizing potential of the compound tested. International standards have been successfully determined using this modification. Such modifications are also authorized in the Note of Guidance SWP/2145/00 of the CPMP (2001) and updated OECD guideline 429.
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)
Species:
mouse
Strain:
NMRI
Sex:
female
Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
2, 10 and 50%
No. of animals per dose:
Six/group
Parameter:
SI
Remarks on result:
other: see Remark
Remarks:
The NMRI mice did not show an increase in the stimulation indices for cell counts or for weights of the draining lymph nodes after application of the test item Dichlororthanilsaure. The "positive level", which is 1.4 for the cell count index, was never reached or exceeded in any dose group.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Non-radioactive method.

The NMRI mice did not show an increase in the stimulation indices for cell counts or for weights of the draining lymph nodes after application of the test item Dichlororthanilsaure. The "positive level", which is 1.4 for the cell count index, was never reached or exceeded in any dose group. The "positive level" of ear swelling, which is 2 x lO EE-2 mm increase, i.e. about 10% of the

control values, has been exceeded in the low and the high dose group .Significant increases compared to vehicle treated animals regarding ear swelling were detected in all dose groups. A clear increase compared to vehicle treated animals regarding ear weights was detected in all groups, which is of statistical significance only in the low dose group.

This study does point to a non-specific (irritant) immunostimulating potential of the test item, but there are no indications for sensitizing properties.

Taken together, no antigen specific activation of the cells of the immune system via dermal route was determined after application of up to and including 50% Dichlororthanilsaure by the method used. Therefore, the concentration of 50% turned out to be the NOEL for the

parameters investigated in this study with respect to skin sensitization.

These findings were verified by the results obtained with the positive control compound Alpha Hexyl Cinnamic Aldehyde.

Interpretation of results:
not sensitising
Executive summary:

No antigen specific activation of the cells of the immune system via dermal route was determined after application of up to and including 50% Dichlororthanilsaure by the method used. Therefore, the concentration of 50% turned out to be the NOEL for the parameters investigated in this study with respect to skin sensitization.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Short description of key information:
In a modified, non-radioactive LLNA, no antigen specific activation of the cells of the immune system via dermal route was determined after application of up to and including 50% Dichlororthanilsaure by the method used. Therefore, the concentration of 50% turned out to be the NOEL for the parameters investigated in this study with respect to skin sensitization.

Justification for selection of skin sensitisation endpoint:
Guideline study

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification