the global clearinghouse for information on alternatives to animal testing

Search Altweb

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

3 April 1998

Dr. William S. Stokes
Environmental Toxicology Program
National Institute of Environmental Health Sciences
P.O. Box 12233
Research Triangle Park, NC 27709

Dear Dr. Stokes:

As promised we have revised our ICCVAM Test Method Submission for the Local Lymph Node Assay (LLNA) based on the comments we secured from Sailstad (Letter dated March 16, 1998). Specifically, we revised Appendix B by giving more detailed information on areas of discordance in the LLNA data. In addition, we have provided disintegration per minute data and stimulation indices for these compounds. The submission was prepared by David Basketter, Ian Kimber and me.

As you know, the LLNA is currently accepted as a screening test in the OECD 406 guidelines as well as in the EU guidelines. In our submission, extensive data are reviewed supporting the use of the LLNA as a stand-alone method for the identification of contact allergens. Comparative studies have confirmed that the local lymph node assay is of equal predictivity to guinea pig methods used currently for the identification of skin sensitizing chemicals. Furthermore, it is clear that the local lymph node assay offers a number of important advantages, including significant animal welfare advantages.

Since the initial publication on the LLNA in 1986 by Timber and his associates, there have been numerous publications addressing the immunological mechanisms underlying the assay as well as its use in regulatory toxicology--61 references are listed in the submission. A list of approximately 200 chemicals which have been tested in the LLNA are listed also in the submission. Of the 130 chemicals tested in one of the reference guinea pig tests, approximately 83% gave the same result in the LLNA and the guinea pig tests.

In light of advancing knowledge and experience, and given animal welfare considerations, it is our opinion that the LLNA is now fully validated as a methodology for the identification of significant skin sensitizers and, therefore, should be adopted formally as an alternative skin sensitization test and incorporated fully into regulatory guideline documents addressing skin sensitization testing. Please note that the proposal relates to the standard LLNA. Consequently, data from modified versions of the LLNA have not been included in the submission.

Please feel free to contact us if you have any questions regarding the submission.

Sincerely yours,
G. Frank Bergerick, Ph.D.
Procter & Gamble Principal Scientist

cc: Dr. I. Kimber, Dr. D. Basketter