Local Lymph Node Assay

Table of Contents

  1. Test Submission
    1. Cover Letter
    2. Submission
  2. Appendices
    1. Local Lymph Node Assay Bibliography
    2. List of Chemicals
      1. Chemicals Tested in Local Lymph Node Assay
      2. Discordant Results Between Local Lymph Node Assay and Guinea Pig or Human Test Methods
      3. Disintegrations Per Minute Data and Stimulation Indices for Discordant Results
    3. Key Local Lymph Node Assay Papers
    4. Sample Local Lymph Node Assay Protocol
    5. ICCVAM Local Lymph Node Assay Test Submission Guidelines

APPENDIX B: Table 2

Discordant Results Between the Local Lymph Node Assay and Guinea Pig or Human Test Methods

Chemical CAS Number LLNA GPMT/BT# HMT MEST
Ammonium thioglycolate1 5421-46-5 + -
Benzocaine2 94-09-7 +/-** +/-** +
Copper chloride3 7758-89-6 + -
5,5-Dimethyl-3-methylenedihydro- 2(3H)-furanone4   + -*
Ethylene glycol dimethacrylate5 97-90-5 + -
Musk ambrette 83-66-9 + -
Neomycin sulphate6 1405-10-3 +/- +
Pyridine7 110-86-1 + +/-
Sodium lauryl sulphate3 151-21-3 + - - -
Xylene 1330-20-7 + -
Benzoyloxy-3,5 benzene dicarboxylic acid8   - +*
5,5-Dimethyl-3-(mesyloxymethyl) dihydro-2(3H)-furanone9   - +*
5,5-Dimethyl-3- (methoxybenzenesulphonyloxymethyl) dihydro-2(3H)-furanone9   - +*
5,5-Dimethyl-3- (nitrobenzenesulphonyloxymethyl) dihydro-2(3H)-furanone9   - +*
Kanamycin6 25389-94-0 - -* +
Nickel chloride9 7718-54-9 - +
Nickel sulphate9 10101-98-1 - + + +
Octadecylmethane sulphonate10 31081-59-1 - +*
Propylparaben11 94-13-3 - - +/-
Sulphanilamide12 63-74-1 - - +
Sulphanilic acid13 121-57-3 - + + +

#Positive results based on EC classification threshold
*Result obtained in a non-standard guinea pig test
**Ref Benzocaine paper

1Significant human contact allergen that should be positive in a predictive test.
2Very, difficult sensitiser in predictive tests is only a human allergen under unique conditions of exposure.
3A false positive in the LLNA.
4Likely to be a true positive based on both the LLNA and structure activity considerations; the guinea pig data are from a nonstandard version of the GPMT that omits the patch induction phase.
5Acrylate allergy is a complex subject, with many acrylate derivatives being suspected of giving rise at least to some degree of clinical disease.
6A well-described contact allergen in medicaments, but which was much weaker than Kanamycin in a human predictive test.
7A very weak allergen in human predictive tests (equivalent to paraben) and which is thus an unexpected positive in the LLNA.
8Whilst this substance was positive in the GPMT (which involves injection), its size and charge will result in extremely poor skin penetration, such that it is unlikely to cause allergic contact dermatitis. Thus, the LLNA result is likely to be the more meaningful.
9False negative in the LLNA.
10A false negative probably due to poor skin penetration engendered by the size of the compound, its very high log P, and the presence of a charged group.
11This substance is a rare allergen except in specific disease states; it is not positive in predictive assays except the human maximization test.
12Unexpected negative in both the LLNA and guinea pig tests.
13Although a clear positive in the GPMT, this substance was negative in both the LLNA and on the basis of substantial human exposure experience, suggesting it is the LLNA result which is correct.