In-vivo administration of recombinant IL-2 increases the number of Thy-1+ dendritic epidermal cells

The number, morphology and response of Thy-1+ dendritic epidermal cells to recombinant interleukin-2 (rIL-2) were investigated in young and aged mice. The Thy-1+ dendritic cells in the aged mice continued to express T-cell receptor (TCR) gamma/delta but differed morphologically from those of the young mice. The aged mice had 50% fewer cells than the young ones. In the rIL-2 treated mice all the Thy-1+ cells were expressed as TCR gamma/delta and exposure to rIL-2 increased the number of these cells in a time- and dose-dependent manner when given systemically and locally. In the aged mice daily injection of rIL-2 increased the number of Thy-1+ dendritic cells within 2 weeks to almost that of young mice, however they had a lower response in the earlier stage. Nude mice showed no response to rIL-2.