UNIT 20.7 The Local Lymph Node Assay (LLNA)

  1. Costanza Rovida1,
  2. Cindy Ryan2,
  3. Serena Cinelli3,
  4. David Basketter4,
  5. Rebecca Dearman5,
  6. Ian Kimber5

Published Online: 1 FEB 2012

DOI: 10.1002/0471140856.tx2007s51

Current Protocols in Toxicology

Current Protocols in Toxicology

How to Cite

Rovida, C., Ryan, C., Cinelli, S., Basketter, D., Dearman, R. and Kimber, I. 2012. The Local Lymph Node Assay (LLNA). Current Protocols in Toxicology. 51:20.7:20.7.1–20.7.14.

Author Information

  1. 1

    CAAT Europe, University of Konstanz, Konstanz, Germany

  2. 2

    Procter & Gamble Company, Cincinnati, Ohio

  3. 3

    Research Toxicology Centre, Pomezia, Rome, Italy

  4. 4

    DabMed Consultancy Ltd., Bedfordshire, United Kingdom

  5. 5

    University of Manchester, Manchester, United Kingdom

Publication History

  1. Published Online: 1 FEB 2012
  2. Published Print: FEB 2012


The murine local lymph node assay (LLNA) is a widely accepted method for assessing the skin sensitization potential of chemicals. Compared with other in vivo methods in guinea pig, the LLNA offers important advantages with respect to animal welfare, including a requirement for reduced animal numbers as well as reduced pain and trauma. In addition to hazard identification, the LLNA is used for determining the relative skin sensitizing potency of contact allergens as a pivotal contribution to the risk assessment process. The LLNA is the only in vivo method that has been subjected to a formal validation process. The original LLNA protocol is based on measurement of the proliferative activity of draining lymph node cells (LNC), as determined by incorporation of radiolabeled thymidine. Several variants to the original LLNA have been developed to eliminate the use of radioactive materials. One such alternative is considered here: the LLNA:BrdU-ELISA method, which uses 5-bromo-2-deoxyuridine (BrdU) in place of radiolabeled thymidine to measure LNC proliferation in draining nodes. Curr. Protoc. Toxicol. 51:20.7.1-20.7.14. © 2012 by John Wiley & Sons, Inc.


  • skin sensitization;
  • in vivo method;
  • LLNA;
  • potency assessment