Promega - Model 4-1BB - Immune Checkpoint Bioassays Cells Brochure

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.