TSLP-activated dendritic cells induce an inflammatory T helper type 2 cell response through OX40 ligand.

We recently showed that dendritic cells (DCs) activated by thymic stromal lymphopoietin (TSLP) prime naive CD4(+) T cells to differentiate into T helper type 2 (Th2) cells that produced high amounts of tumor necrosis factor-alpha (TNF-alpha), but no interleukin (IL)-10. Here we report that TSLP induced human DCs to express OX40 ligand (OX40L) but not IL-12. TSLP-induced OX40L on DCs was required for triggering naive CD4(+) T cells to produce IL-4, -5, and -13.