Interleukin-2 promotes the motility of dendritic cells and their accumulation in lung and skin

Dendritic cells (DC) play a critical role as antigen-presenting cells in vivo. It has previously been shown that DC accumulate in the lung in response to parenteral injections of IFN-gamma. In the current paper, we report that rat DC express the interleukin-2 receptor (IL-2R) alpha-chain (OX-39) and display enhanced motility in response to IL-2 in Boyden chamber and video time-lapse microscopy assays. Increased motility was specifically inhibited by pretreating DC with OX-39 (anti-IL-2R) but not OX-22 (anti-CD45RC), an isotype-matched murine monoclonal antibody. The intratracheal injection of IL-2 increased the number of OX-6+ dendritic cells located around pulmonary venules and in the lung interstitium. When IL-2 was injected into the footpad of the rat. DC were increased around dermal venules at 24 h. This effect was blocked by the parenteral injection of anti-OX-39. We conclude that IL-2 is a potent enhancer of DC motility and may cooperate with other T helper(h)-1 proinflammatory cytokines in attracting DC to sites of inflammation.