4-1BB/CD137/TNFRSF9 Proteins & Antibodies

4-1BB, also known as CD137 or TNFRSF9, is a member of the tumor necrosis factor receptor superfamily and functions as an important costimulatory receptor in immune regulation. Its basal expression is relatively low on resting T cells but can be rapidly induced following T-cell receptor activation. 4-1BB can also be expressed on activated NK cells, dendritic cells, and selected other immune-cell populations. Upon engagement with its ligand 4-1BBL, 4-1BB recruits downstream TRAF proteins and activates signaling pathways including NF-κB and MAPK, thereby promoting lymphocyte proliferation, survival, cytokine production, and memory formation. Because of its ability to enhance antitumor immune responses, 4-1BB has become an important target for agonistic antibodies, conditional immune agonists, bispecific and multispecific molecules, and engineered cell therapies. A key challenge in 4-1BB drug development is achieving effective immune stimulation while minimizing nonspecific or systemic activation.

To support 4-1BB research and antibody development, DIMA BIOTECH provides recombinant ECD proteins from multiple species and extracellular regions, rabbit monoclonal antibodies, biosimilar reference antibodies, and PE- or biotin-conjugated reagents. Domain-specific proteins can be used for ELISA, antibody screening, binding characterization, epitope mapping, and cross-species reactivity studies. Flow cytometry-validated and PE-conjugated antibodies support cell-surface 4-1BB detection, while biotinylated reagents facilitate binding, capture, and screening assays. These tools can be further integrated into agonistic antibody screening, multispecific antibody development, and immune-cell functional evaluation.