CD120b is a 75 kD type I transmembrane protein, also known as Tumor Necrosis Factor Receptor Type II (TNFRII) or p75. It is expressed on a variety of cells at low levels; the expression is upregulated upon activation. This receptor binds both TNF-alpha and LT-alpha (also known as TNF-beta). In association with TRAF1 and TRAF2, the receptor crosslinking induced by TNF-alpha or LT-alpha trimers is critical for signal transduction, leading to apoptosis, NF-kB activation, increased expression of proinflammatory genes, tumor necrosis, and cell differentiation depending on cell type and differentiation state. The TR75-54.7 antibody has been shown to block ligand-induced receptor signaling.