Definition

A human immunoglobulin G4 (IgG4) monoclonal antibody directed against the inhibitory immune checkpoint receptor Ig-like transcript 2 (ILT2; leukocyte immunoglobulin-like receptor subfamily B member 1; LILRB1; leukocyte immunoglobulin-like receptor 1; LIR1; monocyte/macrophage immunoglobulin-like receptor 7; MIR-7; CD85j), with potential immunomodulating and antineoplastic activities. Upon intravenous administration, anti-ILT2 monoclonal antibody AGEN1571 targets and binds to ILT2. This prevents the binding of ILT2 ligands, including the immunosuppressive MHC molecule HLA class I histocompatibility antigen, alpha chain G (HLA-G; human leukocyte antigen G), to the ILT2 receptor and prevents ILT2-mediated signaling. This inhibits ILT2-mediated immune suppression, thereby promoting both innate and adaptive immune responses and may result in the activation of anti-tumor immune responses. ILT2, a transmembrane protein and inhibitory member of the immunoglobulin-like transcript (ILT) family of proteins, is expressed on both innate and adaptive immune cells. HLA-G, an immune checkpoint normally expressed at the maternal-fetal interface, is expressed across multiple tumor types and plays a key role in cancer immune evasion.