Cytokine that binds to TNFRSF3/LTBR. Binding to the decoy receptor TNFRSF6B modulates its effects. Activates NFKB and stimulates the proliferation of T-cells. Acts as a ligand for TNFRSF14/HVEM. Upon binding to TNFRSF14/HVEM, delivers costimulatory signals to T cells, leading to T cell proliferation and IFNG production (By similarity). Homotrimer. Interacts with TNFRSF14. The soluble form derives from the membrane form by proteolytic processing. Belongs to the tumor necrosis factor family.