4-1BB (CD137/TNFRSF9), a member of the tumor necrosis factor receptor superfamily, is an inducible co-stimulatory receptor expressed on T cells, natural killer (NK) cells and innate immune cell populations. When present on the cell surface, 4-1BB interacts with 4-1BB ligand (4-1BBL) and induces subsequent cell proliferation and production of interferon gamma (IFNγ) and interleukin-2 (IL-2), particularly in T and NK cells.
Current methods used to measure the activity of biologic drugs targeting 4-1BB rely on assays that are laborious and highly variable due to their reliance on donor primary cells, complex assay protocols and unqualified assay reagents and, as a result, are difficult to establish in a quality-controlled, drug-development setting.
The 4-1BB Bioassay is a biologically relevant, MOA-based assay that can be used to measure the potency and stability of ligands or agonist antibodies that can bind and activate 4-1BB.
Control Ab, Anti-4-1BB, is a mouse anti-human 4-1BB agonist antibody. It can be used as a positive control in the 4-1BB Bioassay in the presence of FcγRIIb CHO-K1 Cells (Cat.# JA2251, JA2255).