Leukemia-associated peptide-Major Histocompatibility Complex (pMHC)

Leukemia-associated peptide-Major Histocompatibility Complex (pMHC) complexes are molecular assemblies on the surface of leukemic cells that present short, processed peptide fragments derived from intracellular leukemia-associated antigens (LAAs) to the immune system (Source: Nature Reviews Immunology). These complexes are formed when LAAs, such as Wilms Tumor 1 (WT1), PRAME, or Proteinase 3, are degraded by the proteasome and transported into the endoplasmic reticulum, where they bind to MHC class I molecules before being trafficked to the cell membrane (Source: Blood). Because many leukemia-specific proteins are intracellular and thus inaccessible to standard monoclonal antibodies, pMHC complexes represent a critical class of targets for immunotherapies like TCR-engineered T-cells (TCR-T) and TCR-like antibodies (Source: Frontiers in Immunology). These therapies are designed to recognize the specific combination of the peptide and the MHC groove, allowing for the selective destruction of malignant cells while sparing healthy tissues that do not present the specific pMHC (Source: Journal of Hematology & Oncology). However, the effectiveness of targeting these complexes can be limited by the high degree of HLA polymorphism in the human population and the ability of tumor cells to evade the immune system by downregulating MHC expression (Source: Cancer Discovery).

Other names

pHLA complexLeukemia-associated antigen-MHC complexpMHCTumor-specific peptide-MHCPeptide-Human Leukocyte Antigen complex

Recognition by T-cell receptors (TCRs) or TCR-like antibodies, leading to T-cell activation, cytokine release, and cytotoxic lysis of the leukemia cell.