The murine local lymph node assay (LLNA) has been developed as an alternative to guinea pig models for the assessment of the contact sensitization potential. However, there is a need to develop a non-radioisotopic endpoint for the LLNA because of the radioisotopic method's requiring the use of special facilities. In this study, we investigated to evaluate the populations of intracellular cytokine producing cells and to analyze the expression of mRNA levels in the lymph node (LN) cells following allergen and irritant. Female Balb/c mice were treated by the topical application on the dorsum of both ears with strong sensitizers, 2,4-dinitrochlorobenzene (DNCB) and toluene diisocyanate (TDI) and a strong irritant, sodium lauryl sulfate (SLS), once daily for 3 consecutive days. The lymph node cells were harvested 72h after the final treatment. The analysis of intracellular cytokine cell in LN cells was performed with a flow cytometry. Mice were treated with DNCB and TDI showed a preferential increase in the percentage of CD4+IL-2+ cells compared with vehicle and irritant-treated mice. There was an increase in CD4+IFN-g+ cells of mice treated with DNCB and TDI, but no significant increases were observed in mice treated with SLS. Mice were treated with DNCB and TDI showed an increase in the percentage of CD4+IL-4+ cells compared with vehicle and irritant-treated mice. There was an increase in the mRNA level for interleukin 4 (IL-4) in mice treated with DNCB and TDI, but no significant increases were observed in mice treated with SLS. These results suggest that the population of interferon-gamma (IFN-g+) and IL-4+ cells on CD4+ cells and the mRNA expression for IL-4 in lymphocytes could be selectively modulated in allergen-treated mice.