6. Test no. 442B: skin sensitization. Local lymph node stimulation test (BrdU- ELISA)

The local lymph node stimulation BrdU-ELISA (ELGL: BrdU-ELISA) is a non-radioactive variant of the ELGL method designed to identify sensitizing chemicals and measure the lymphocyte proliferation they induce in auricular lymph nodes. This method, described in mice (CBA/JN strain), is based on the quantification of 5-bromo-2-deoxyuridine (BrdU), a thymidine analog, in lymphocyte DNA, as an indicator of this proliferation.

A minimum of four animals is used per dose group, with a minimum of three concentrations of test substance, plus a negative control group treated with vehicle alone, and a positive control, if required. The experimental protocol lasts six days. The animals are then euthanized and a single-cell suspension of lymph node cells (LNCs) is prepared. The LMC dispersion procedure is a crucial step, particularly for the very small lymph nodes in the negative...