A MODIFICATION OF THE LOCAL LYMPH-NODE ASSAY FOR CONTACT ALLERGENICITY SCREENING - MEASUREMENT OF INTERLEUKIN-2 AS AN ALTERNATIVE TO RADIOISOTOPE-DEPENDENT PROLIFERATION ASSAY

The local lymph node assay is an effective prediction method for contact allergenicity, but employs radioisotopes. We investigated whether measurement of interleukin-2 (IL-2) production by lymph node cells-could be used instead to predict contact allergenicity of chemicals. Test chemicals were applied for three consecutive days to both ears of Balb/c mice and the auricular lymph nodes were obtained on either the fourth or fifth day after the first application. Both IL-2 concentration in supernatant of the suspension and proliferative activity of lymph node cells were determined after 24-, 48-, 72-h cell culture in RPMI-1640 medium by ELISA and by measuring [H-3]methylthymidine incorporation, respectively. These two methods detected allergenicity similarly except in the case of TNCB and oxazolone, which showed excessive proliferation-inducing capacity as compared to IL-2 release-increasing effect. Flow cytometry showed that these two chemicals also increased the percentage of Ia(d)-positive cells in the lymph nodes, suggesting that these chemicals might induce not only, cellular immunity but also humoral immunity. We conclude that interleukin-2 assay is a convenient and dependable method for screening strong contact allergens without using radioisotopes.