Tumor necrosis factor-alpha (TNF-α) is a type II transmembrane protein that exists in a membrane-bound form (mTNF-α). mTNF-α can be processed into a 17 kDa soluble TNF-α (sTNF-α) through the action of TNFα converting enzyme. TNF-α exerts its function through two TNF receptor superfamily members, TNF receptor 1 (TNFR1) and TNF receptor 2 (TNFR2).Antibody-dependent cell-mediated cytotoxicity (ADCC) refers to the immune cells expressing Fc receptors directly killing target cells by recognizing the Fc portion of antibodies. Nowadays, the mechanism of ADCC is used to evaluate the efficacy of antibodies or target cells. The binding of antibodies to target antigens on cell surfaces leads to the activation of the ADCC pathway if the Fc portion of the antibody binds to the Fc γ RIIIa receptor on the surface of effector cells (mainly natural killer cells). The killing of target cells is the endpoint of this activation pathway, which is used in classical ADCC bioactivity assays. These assays utilize donor peripheral blood mononuclear cells (PBMC) or natural killer (NK) cell subsets as effector cells, but these cells exhibit high variability in response, are challenging to prepare, and can lead to high background readings. Membrane Bound TNFα (cleavage-resistant) CHO-K1 Cell Line, which overexpresses TNF-α protein that is resistant to TNFα converting enzyme cleavage on CHO-K1 cells, providing a stable cell line capable of expressing TNFα on the cell surface. It can be used as target cells for studying the ADCC efficacy of TNFα blocking antibodies, as well as for determining the affinity of TNFα antibodies.
