Cutaneous immune responses to 2, 4-dinitrochlorobenzene (DNCB): role of interleukin (IL)-2 (97.15)

Abstract Prolonged topical exposure of BALB/c strain mice to the contact allergen DNCB, or to the respiratory sensitiser trimellitic anhydride, results in T helper (h) 1 and Th2 cell polarisation, respectively. In addition, a single application of allergen results in discrete cutaneous cytokine profiles and the migration of Langerhans’ cells (LC) with different tempos. Of note, DNCB only induced a rapid and transient increase in cutaneous IL-2. We have now explored the role of IL-2 in DNCB-induced LC migration. BALB/c mice received an intradermal injection of recombinant IL-2 or IL-1β (50ng/ear); the latter is known to provoke LC migration. LC densities were determined in epidermal sheets by immunofluorescence staining. Cytokine production by skin explants was measured by protein array. Intradermal injection of IL-1β decreased epidermal LC numbers significantly after 4 and 16h whereas IL-2 was without effect. Prior systemic administration of neutralising anti-IL-2 antibody failed to influence LC migration monitored 6h after DNCB treatment. Migration was blocked by treatment with an anti-tumor necrosis factor-α antibody, a cytokine regulator of LC migration. Administration of IL-2 did result in increased expression of cutaneous IL-17. These data show that IL-2 is not involved in LC migration, however, the selective up-regulation of IL-2 by DNCB may play a role in the subsequent polarisation of the immune response.