TNF is secreted by macrophages, monocytes, neutrophils, T-cells, NK-cells following their stimulation by bacterial LPS. Cells expressing CD4 secrete TNF-alpha while CD8 cells secrete little or no TNF-alpha. The synthesis of TNF-alpha is induced by many different stimuli including interferons, IL2, GM-CSF. TNF-β is a potent mediator of inflammatory and immune responses. It belongs to the TNF family of ligands, and signals through TNFR1 and TNFR2. TNF-β is produced by activated T and B lymphocytes, and has similar activities to TNF-α. It mediates a large variety of inflammatory, immunostimulatory, and antiviral responses.  
Recombinant Human TNF-β produced in E. coli is is a glycosylated polypeptide chain of 172 amino acids. A fully biologically active molecule,rhTNF-β has a molecular mass of 18.6 kDa analyzed by reducing SDS-PAGE and is obtained by chromatographic techniques at ExCell Bio.