Definition

A humanized immunoglobulin G1 (IgG1) monoclonal antibody directed against the inhibitory immune checkpoint receptor immunoglobulin-like transcript 4 (LILRB2; ILT4; leukocyte immunoglobulin-like receptor subfamily B member 2; lymphocyte immunoglobulin-like receptor 2; LIR2; monocyte/macrophage immunoglobulin-like receptor 10; MIR-10; CD85d), with potential immunomodulating and antineoplastic activities. Upon administration, anti-LILRB2 monoclonal antibody OR502 targets and binds to LILRB2. This prevents the binding of LILRB2 ligands to their receptor and prevents LILRB2-mediated signaling. This abrogates the immunosuppressive activities of LILRB2 in the tumor microenvironment (TME), activates the expression of pro-inflammatory cytokines, including granulocyte macrophage-colony-stimulating factor (GM-CSF) and tumor necrosis factor alpha (TNFalpha), and enhances a cytotoxic T-lymphocyte (CTL)-mediated anti-tumor immune response. LILRB2, a transmembrane protein and inhibitory member of the immunoglobulin-like transcript (ILT) family of proteins, is expressed primarily by myeloid cells, including monocytes, macrophages, dendritic cells (DCs) and granulocytes, and in certain tumors. It plays a key role in tumor immune evasion.