An Evaluation of Performance Standards and Non-radioactive Endpoints for the Local Lymph Node Assay

This is the report of the 65th of a series of workshops organised by the European Centre for the Validation of Alternative Methods (ECVAM). The main objective of ECVAM, as defined in 1993 by its Scientific Advisory Committee (ESAC), is to promote the scientific and regulatory acceptance of alternative methods which have scientific relevance and which reduce, refine or replace the use of laboratory animals. One of the first priorities set by ECVAM was the implementation of procedures that would enable it to become well-informed about the state-of-the-art of non-animal test development and validation, and of opportunities for the possible incorporation of alternative methods into regulatory procedures. It was decided that this would be best achieved through a programme of ECVAM workshops, each addressing a specific topic, and at which selected groups of independent international experts would review the current status of various types of in vitro tests and their potential uses, and make recommendations about the best way forward. A Workshop on An Evaluation of Performance Standards and Non-radioactive Endpoints for the Local Lymph Node Assay was held at ECVAM on 25–27 September 2007, under the chairmanship of David Basketter. The workshop was attended by experts from academia, industry, national organisations, and national and international validation authorities. At present, the local lymph node assay (LLNA) involves the use of radiolabelled thymidine as part of the standard protocol. The aim of the workshop was to review the status of methods which employ non-radioactive endpoints for the LLNA and to consider Performance Standards for their eventual assessment. At the end of the report are listed recommendations that should be considered for progressing toward the validation of relevant and reliable methods.