INTERLEUKIN-6 (IL-6) PRODUCTION BY LYMPH-NODE CELLS - AN ALTERNATIVE END-POINT FOR THE MURINE LOCAL LYMPH-NODE ASSAY

The murine local lymph node assay has been developed for the identific ation of contact allergens. Sensitization potential is measured as a f unction of proliferation (radiolabeled thymidine incorporation) in lym ph nodes draining the site of exposure to the test chemical. In the pr esent study, an alternative endpoint for the local lymph node assay ha s been evaluated: the production by draining lymph node cells (LNC) of interleukin 6 (IL-6), a cytokine involved in immunoregulatory and inf lammatory responses. After topical exposure to a variety of contact se nsitizing and nonsensitizing chemicals, proliferation and IL-6 product ion were measured in parallel cultures of draining LNC. A clear associ ation between the vigour of proliferative activity and IL-6 production was observed. Eight of 10 sensitizing chemicals induced measurable (> 150 pg/ml) IL-6 production. Nonsensitizing chemicals, including nonse nsitizing skin irritants, failed to stimulate detectable levels of IL- 6. These data indicate that the production of IL-6 by allergen-activat ed LNC may provide a valuable, nonisotopic modification of the local l ymph node assay for the identification of moderate and strong contact allergens.