Lymphotoxin

Lymphotoxin (previously known as tumor necrosis factor-beta) is a lymphokine cytokine.

It is a protein that is produced by Th1 type T-cells and induces vascular endothelial cells to change their surface adhesion molecules to allow phagocytic cells to bind to them.

Lymphotoxin is homologous to Tumor Necrosis Factor beta, but secreted by T-cells. It is paracrine due to the small amounts produced. The effects are similar to TNF-alpha, but TNF-beta is also important for the development of lymphoid organs.