Overview
The murine local lymph node assay (LLNA) is a test method for assessing the hazard potential
of a test substance to induce allergic contact dermatitis in humans.
ICCVAM has recommended that two modified versions of the LLNA that do not use radioactive isotopes
can be used to identify substances as potential skin sensitizers or nonsensitizers, with certain
limitations. The availability of LLNA methods that do not use radioactivity is expected to allow
more institutions to take advantage of the animal welfare benefits of the LLNA and provides
environmental benefits as well. Federal agencies accepted or endorsed the ICCVAM recommendations
on the modified versions of the LLNA in 2011.
View letters to Federal agencies communicating ICCVAM recommendations
Background
In January 2007, the U.S. Consumer Product Safety Commission (CSPC) requested that NICEATM and
ICCVAM assess the validation status of new versions and applications of the LLNA. The CPSC
nomination included a request that ICCVAM evaluate three modified versions of the LLNA not requiring
the use of radioactive markers:
- The LLNA: BrdU-ELISA, which measures the nucleotide analog bromodeoxyuridine (BrdU)
using an enzyme-linked immunosorbent assay (ELISA) to assess lymph node cell proliferation
- The LLNA: DA, which measures adenosine triphosphate content
as an indicator of lymph node cell proliferation
- The LLNA: BrdU-FC, which measures BrdU using flow cytometry
to assess lymph node cell proliferation
The ICCVAM interagency Immunotoxicity Working Group (IWG), working with NICEATM, prepared draft
background review documents (BRDs) and draft recommendations for the three modified versions of the
LLNA. The draft BRDs and draft ICCVAM recommendations on these methods were reviewed in a public meeting
of an international independent scientific peer review panel (“Panel”) in March 2008. The Panel agreed
with the ICCVAM assessment that more data were needed to
evaluate these new versions of the LLNA. Additional data were submitted to
NICEATM; NICEATM and the interagency IWG revised the BRDs,
and updated test method recommendations were developed by ICCVAM. A second Panel
meeting to consider the revised documents was held in April 2009, and the Panel's report
was made available in June 2009. ICCVAM considered the Panel’s report along with all public and
SACATM comments received as they prepared final test method recommendations, which were forwarded to Federal
agencies for their consideration in June 2010.
ICCVAM recommended that the LLNA: DA and the LLNA: BrdU-ELISA be used to identify substances as
potential skin sensitizers or nonsensitizers, with certain limitations. ICCVAM deferred
a formal recommendation on the validity of the LLNA: BrdU-FC until an independent audit of all data
supporting the analysis has been conducted and until transferability has been demonstrated in an
interlaboratory validation study.
View Federal Register notice announcing receipt of agency responses to recommendations (76 FR 2388, January 13, 2011)
[PDF]
NICEATM and ICCVAM, in conjunction with the Japanese Center for the Validation of Alternative Methods,
developed new draft test guidelines for use of the LLNA: DA and LLNA:
BrdU-ELISA and submitted them to the Test Guidelines Programme of the Organisation for Economic
Co-operation and Development. The new test guidelines, designated Test Guidelines 442A (LLNA: DA)
and 442B (LLNA: BrdU-ELISA) were adopted by the OECD in July 2010.
View OECD Test Guideline 442A — Skin Sensitization: Murine Local Lymph Node Assay: DA
[PDF]
View OECD Test Guideline 442B — Skin Sensitization: Murine Local Lymph Node Assay: BrdU-ELISA
[PDF]
View publications and presentations on ICCVAM evaluations of the murine local
lymph node assay for identification and classification of sensitizers
Federal Register Notices with Announcements Relevant to the ICCVAM Evaluation
of the Nonradioactive LLNA Methods
Independent Scientific Peer Review Panel Report: Updated Validation Status of New Versions and
Applications of the Murine Local Lymph Node Assay: A Test Method for Assessing the Allergic Contact
Dermatitis Potential of Chemicals and Products: Notice of Availability and Request for Public
Comments
Announcement of a Second Meeting of the Independent Scientific Peer Review Panel on the Murine
Local Lymph Node Assay; Availability of Draft Background Review Documents (BRD); Request for Comments
Peer Review Panel Report on the Validation Status
of New Versions and Applications of the Murine Local Lymph Node Assay
(LLNA): A Test Method for Assessing the Allergic Contact Dermatitis
Potential of Chemicals and Products: Notice of Availability and Request for Public Comments
Announcement of an Independent Scientific Peer Review Panel Meeting on the Murine Local Lymph
Node Assay; Availability of Draft Background Review Documents; Request for Comments
|
View Federal Register Notice
(73 FR 1360, January 8, 2008) [PDF] |
Murine Local Lymph Node Assay: Request for Comments, Nominations of Scientific Experts, and
Submission of Data
|
View Federal Register notice
(72 FR 27815, May 17, 2007) [PDF]
View comments received in response to the Federal Register notice |
|
View the CPSC nomination letter [PDF] |
Information about the 1998 LLNA Peer Panel meeting
|
