Ly-6A/E induction by interleukin-6 and interleukin-9 in T cells

Interleukin-6 (IL-6) is active in the early steps of T cell activation and confers IL-2 responsiveness. In this work, we used EL4 T lymphoma to identi fy IL-6 target genes in T cells, By differential screening of a cDNA librar y, we found that IL-6 induced the expression of Ly-6A/E, a GPI-anchored cel l surface protein reported to be a regulator of T cell activation, In addit ion to IL-6, IL-9 and IFN-(gamma) induced Ly-6A/E expression in EL4 and BW5 147 cells, We showed that both IL-6 and IL-9 mediated the transcriptional a ctivation of Ly-6A/E through a GAS element in the Ly-6A/E promoter, which w as able to bind STAT1 and STAT3, transcription factors activated by these c ytokines, IL-6 had a similar effect in freshly isolated normal T cells, and dramatically increased their proliferation upon Ly-6A/E stimulation, Taken together, our data suggest that Ly-6A/E induction takes part in the T cell activation program initiated by IL-6.