ROR1/CD3/PD-L1/4-1BB Antibodies

Target Information

ROR1 (Receptor Tyrosine Kinase-Like Orphan Receptor 1) is a surface protein primarily expressed during embryonic development, where it contributes to organ formation, neural development, and progenitor cell survival. It is largely absent from normal adult tissues, except for low levels in immature B cell precursors and adipocytes. ROR1 is overexpressed in several malignancies, including chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), acute lymphoblastic leukemia (ALL), marginal zone lymphoma, and lung adenocarcinoma, where it functions as a survival factor. Originally identified as an orphan receptor related to Trk family kinases, ROR1 is now thought to interact with Wnt-5a and may function as a pseudokinase. It promotes tumor cell proliferation and resistance to apoptosis, partly through AKT pathway activation. Structurally, ROR1 is a glycoprotein containing extracellular Ig-like, Frizzled, and Kringle domains, and an intracellular tyrosine kinase-like domain.

CD3 is a multi-subunit complex (gamma, delta, epsilon, zeta) required for T cell receptor (TCR) assembly and signaling. Expressed on thymocytes and mature T cells, CD3 transduces antigen-recognition signals via tyrosine-based motifs in its cytoplasmic tails, driving T cell activation, proliferation, and survival. CD3 defects cause immunodeficiency.

PD-L1 (B7-H1) binds PD-1 on T cells to inhibit TCR signaling, reducing proliferation and cytokine production. Frequently overexpressed in tumors and inducible by IFN-γ, PD-L1 enables tumor immune evasion.

CD137 (4-1BB, TNFRSF9) is an inducible costimulatory receptor on activated T cells. Interaction with its ligand (4-1BBL) enhances T cell survival, expansion, and memory formation, and regulates cytokine production. Soluble CD137 may modulate immune responses.