Proteinase 3-derived peptide PR1 bound to HLA class I histocompatibility antigen A*02:01 (PR1/HLA-A2 complex)

The PR1/HLA-A2 complex is a peptide-MHC class I molecule, where the PR1 peptide (VLQELNVTV, a nonamer) derived from proteinase 3 and neutrophil elastase is presented on the cell surface by the HLA-A*02:01 molecule. This complex is specifically recognized by cytotoxic T lymphocytes and monoclonal antibodies, making it a well-studied target for immunotherapy in acute/chronic myeloid leukemia. It is not a traditional receptor or enzyme, but an immune complex critical to adaptive immune recognition and a central neoantigen in targeted cancer therapy. The PR1 peptide is processed and presented by leukemic (and some normal myeloid) cells, enabling immune targeting in HLA-A2–positive patients. PR1/HLA-A2 surface abundance serves as a biomarker and basis for approaches including TCR-based therapies and antibody immunotherapy.

Other names

PR1 peptide–HLA-A2 complexPR1-HLA-A2PR1/HLA-A*02:01PR1-MHC class I complex

Immune-mediated cytotoxicity via T cells recognizing PR1/HLA-A2 on leukemic cells; Antibody-dependent cellular cytotoxicity (e.g., by 8F4 mAb); Complement-dependent cytotoxicity.