Cathepsin G-derived leader-sequence peptide (CG1)

CG1 is a leader-sequence–derived peptide (FLLPTGAEA) from the azurophil granule serine protease cathepsin G (CTSG) that is naturally processed and presented in complex with HLA-A*02:01 (HLA-A2) on the surface of myeloid leukemia blasts, particularly in acute myeloid leukemia (AML) and some chronic myeloid leukemia (CML) blast crisis cell lines. CG1 is not a receptor, enzyme, transporter, or full-length protein, but rather a short tumor-associated antigenic peptide recognized by cytotoxic T lymphocytes and by engineered TCR-mimic and bispecific antibodies (e.g., CG1/HLA-A2 × CD3) that can mediate potent, HLA-A2‑restricted T‑cell–dependent killing of CG1/HLA-A2–positive leukemia cells while sparing normal hematopoietic stem cells and HLA-A2–positive granulocytes in preclinical studies.

Other names

CG1 (cathepsin G–derived leader-sequence peptide presented by HLA-A*02:01)

T‑cell redirection against CG1/HLA-A2–positive myeloid leukemia cells via bispecific antibody binding CG1/HLA-A2 on leukemic blasts and CD3 on T cells, leading to T‑cell activation and cytotoxicity