function:Cytokine that binds to TNFRSF9. Induces the proliferation of activated peripheral blood T-cells. May have a role in activation-induced cell death (AICD). May play a role in cognate interactions between T-cells and B-cells/macrophages.,similarity:Belongs to the tumor necrosis factor family.,subunit:Homotrimer .,tissue specificity:Expressed in brain, placenta, lung, skeletal muscle and kidney.,