TRANCE, a TNF family member, is differentially expressed on T cell subsetsand induces cytokine production in dendritic cells

TNF-related activation-induced cytokine (TRANCE) is a member of the TNF fam ily recently identified in activated T cells. We report here that TRANCE mR NA is constitutively expressed in memory, but not naive, T cells and in sin gle-positive thymocytes. Upon TCR/CD3 stimulation, TRANCE mRNA and surface protein expression are rapidly up-regulated in CD4(+) and CD8(+) T cells, w hich can be further enhanced on CD4(+) T cells by CD28-mediated costimulati on. However, TRANCE induction is significantly suppressed when cells are st imulated in the presence of IL-4, but is not modified in the presence of IF N-alpha, IFN-gamma, TGF-beta, TNF-alpha, or IL-2. High levels of TRANCE rec eptor expression are found on mature dendritic cells (DCs), In this study w e show that activated T and B cells also express TRANCE receptor, but only at low levels, TRANCE, however, does not exert any significant effect on th e proliferation, activation, or survival of those cells. In DCs, TRANCE ind uces the expression of proinflammatory cytokines (IL-6, IL-1) and T cell gr owth and differentiation factors (IL-12, IL-15) in addition to enhancing DC survival. Moreover, TRANCE cooperates with CD40 ligand or TNF-alpha to fur ther increase the viability of DCs, suggesting that several TNF-related mol ecules on activated T cells may cooperatively regulate the function and sur vival of DCs to enhance T cell-mediated immune responses.