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Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Performed similar to OECD 429 guideline, Read-across from Manganese chloride resp. Lead acetate. However, the study performance is well-documented and meets scientific principles which indicates that the study is well-performed and suitable to cover this endpoint.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Identification of Metal Allergens in the Local Lymph Node Assay
Author:
Basketter DA, Lea LJ, Cooper KJ, Ryan CA, Gerberick GF, Dearman RJ, Kimber I
Year:
1999
Bibliographic source:
American Journal of Contact Dermatitis Vol. 10, No. 4 (December), 1999: pp 207-212
Reference Type:
publication
Title:
The murine local lymph node assay: A commentary on collaborative studies and new directions
Author:
Kimber I, Basketter DA
Year:
1992
Bibliographic source:
Fd. Chem. Toxic. Vol. 30, No. 2, pp. 165-169, 1992

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
yes
Remarks:
Dose concentrations: 25, 10, 5 % (w/v) (MnCl2) resp. 10, 5, 2.5 % (w/v) (Lead acetate)
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Reference substance name:
Manganese chloride
IUPAC Name:
Manganese chloride
Constituent 2
Chemical structure
Reference substance name:
Lead acetate
EC Number:
239-379-4
EC Name:
Lead acetate
Cas Number:
15347-57-6
Molecular formula:
C2H4O2.xPb
IUPAC Name:
lead(4+) tetraacetate
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): Manganese chloride (Manganese (Mn)); Lead acetate
- Substance type: inorganic salt
- Physical state: solid
- Analytical purity: 97% (manganese chloride), >99% (lead acetate)
- Impurities (identity and concentrations): no data
- Other: Supplier: Sigma, Poole, United Kingdom

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/Ca
Sex:
not specified
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Olac, Bicester, United Kingdom
- Age at study initiation: young adult, 7 - 12 weeks
- Weight at study initiation: no data
- Housing: four mice per group are caged separately
- Acclimation period: at least 2 days

Study design: in vivo (LLNA)

Vehicle:
other: petrolatum (manganese chloride), DMSO (lead acetate)
Concentration:
25, 10, 5 % (w/v) (manganese chloride)
10, 5, 2.5 % (w/v) (lead acetate)
No. of animals per dose:
4
Details on study design:
RANGE FINDING TESTS:
The dose selection is made to provide the highest possible test concentration, while avoiding unacceptable dermal trauma or systemic toxicity

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: ³H-Thymidine incorporation
- Criteria used to consider a positive response: For each concentration of test material a stimulation index is derived, using values from vehicle control nodes as the comparator. On the basis of local lymph node assay responses, chemicals are classified as either "sensitizers" or "not strong sensitizers". There are two criteria for a positive response. First, at least one concentration of the test chemical must induce a three-fold or greater increase in 3H-thymidine incorporation compared with vehicle control values. Secondly, the data must not be incompatible with a conventional biological dose response. Chemicals that fail to induce a three-fold or greater response at any test concentration are classified as being not strong sensitizers. In practice, equivocal results will suggest that a repeat test, if possible using higher application concentrations, is appropriate.

TREATMENT PREPARATION AND ADMINISTRATION:
25 µl of each treatment concentration or an equal volume of the vehicle alone are applied to the dorsum of both ears ensuring even distribution. Treatment is performed daily for 3 consecutive days.
Statistics:
no data

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: Stimulation index (SI) dependent on the test concentration Manganese chloride: SI = 1.1 (5 %) SI = 0.6 (10 %) SI = 1.0 (25 %) Lead acetate: SI = 0.7 (2.5 %) SI = 0.8 (5 %) SI = 1.0 (10 %)
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: no data

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The study was performed similar to OECD 429 guideline on the Read-across substance Manganese chloride for the cation resp. Lead acetate for the anion of Manganese (II) acetate. The study performance is well-documented and meets scientific principles which indicates that the study is well-performed and suitable to cover this endpoint. Therefore, the results can considered to be reliable and sufficient for the assessment of the sensitizing properties of manganese (II) acetate.
Both substances exhibited at all tested concentrations (which are also considered to be of a sufficient magnitude) a stimulation index not greater than 1.1, so it can be concluded, that neither the cation Mn2+ nor the anion CH3COO- have sensitizing properties and consequently also Manganese (II) chloride is not sensitizing. So, Manganese (II) acetate does not need to be classified as skin sensitizing according regulation 1272/2008/EC nor according directive 67/548/EEC.
Executive summary:

In a dermal sensitization study similar to OECD 429 (murine local lymph node assay) with manganese chloride (25, 10, 5 % (w/v)) and lead acetate (10, 5, 2.5 % (w/v)) in petrolatum resp. DMSO, 7-12 week old CBA/Ca mice (4 animals / dose group) were tested using the ³H-thymidine incorporation method. The test substance was applied on three consecutive days on the dorsum of each ear, local lymph nodes were isolated on the fifth day, 5 h after ³H-thymidin was injected in the tail vein, and beta-scintillation was measured. No clinical signs and mortality was recorded. The stimulation index (SI) was determined to be 0.6 – 1.1 for both substances, so manganese (II) acetate is not a dermal sensitizer. This study is considered to be reliable and to fulfill the requirements for a study similar to OECD 429.