Leukemia-associated antigen peptide–major histocompatibility complex (LAA-pMHC)

Leukemia-associated antigen peptide–major histocompatibility complex (LAA-pMHC) complexes are molecular assemblies on the surface of leukemic cells that present intracellular protein fragments to the immune system. These complexes consist of a peptide derived from leukemia-associated antigens (LAAs)—such as Wilms' Tumor 1 (WT1), PRAME, or Proteinase 3—bound to Major Histocompatibility Complex (MHC) molecules, primarily HLA Class I (Dao et al., 2013, Science Translational Medicine). Because many oncogenic drivers in leukemia are intracellular and inaccessible to traditional antibodies, the pMHC complex serves as a vital therapeutic window for T-cell-based interventions. Therapeutic strategies targeting these complexes include TCR-engineered T-cells (TCR-T), TCR-like antibodies, and peptide vaccines designed to trigger a specific cytotoxic T-lymphocyte (CTL) response (Molldrem et al., 2000, Nature Medicine). The specificity of these therapies is determined by the unique combination of the peptide sequence and the specific HLA allele, making patient HLA-typing a prerequisite for treatment. However, challenges such as HLA downregulation by tumor cells and potential cross-reactivity with similar peptides in healthy tissues (on-target, off-tumor toxicity) remain significant hurdles in clinical development (Yasukawa et al., 2002, Blood).

Other names

Leukemia-associated antigen peptide-HLA complexTumor-associated antigen peptide-MHC complexpMHC complexLeukemia-specific antigen-MHC complexT-cell receptor ligand

Targeted T-cell mediated cytotoxicity via T-cell receptor (TCR) recognition of peptide-MHC complexes or antibody-dependent cellular cytotoxicity (ADCC) via TCR-like antibodies.