INTERLEUKIN-1-BETA AND THE STIMULATION OF LANGERHANS CELL-MIGRATION -COMPARISONS WITH TUMOR-NECROSIS-FACTOR-ALPHA

Epidermal Langerhans cells (LC) and the cells into which they mature a re believed to play a pivotal role in cutaneous immune function, The i nduction phase of contact sensitization is associated with the migrati on of LC from the skin and their accumulation as dendritic cells (DC) in lymph nodes draining the site of exposure, We have demonstrated pre viously that tumour necrosis factor alpha (TNF-alpha), an epidermal cy tokine produced by keratinocytes, provides one signal for LC migration , We describe here experiments designed to evaluate the influence of i nterleukin 1 beta (IL-1 beta), a product exclusively of LC in murine e pidermis, on LC migration, LC morphology and DC accumulation, and to c ompare the effects of this cytokine with those of TNF-alpha. Both cyto kines induced a significant reduction in the frequency of epidermal LC and the arrival of DC in draining lymph nodes, Changes in both parame ters were induced more rapidly following intradermal administration of TNF-alpha than were observed after treatment with IL-1 beta. However, the reduction in LC frequency was more persistent with IL-1 beta. Bot h cytokines caused the activation of LC, characterized by the acquisit ion of a more dendritic morphology and the increased expression of Ia molecules, These results demonstrate that IL-1 beta and TNF-alpha can each stimulate the migration of epidermal LC, but that the changes ind uced by these cytokines are not identical.