Lymphotoxin-alpha (LT-alpha) or Tumor necrosis factor-beta (TNF-β) is a protein that in humans is encoded by the LTA gene. Lymphotoxin alpha, a member of the tumor necrosis factor family, is a cytokine produced by lymphocytes. LTA is highly inducible, secreted, and exists as homotrimeric molecule. LTA forms heterotrimers with lymphotoxin-beta, which anchors lymphotoxin-alpha to the cell surface. LTA mediates a large variety of inflammatory, immunostimulatory, and antiviral responses. LTA is also involved in the formation of secondary lymphoid organs during development and plays a role in apoptosis. Lymphotoxin alpha has been shown to interact with LTB.