Walnut allergen peptide-MHC class II complex (Walnut pMHCII-TCR complex)

The walnut allergen peptide-MHC class II complex is a critical immunological assembly involved in the pathogenesis and treatment of walnut allergy (Juglans regia). This complex forms when walnut-derived proteins, such as Jug r 1 (2S albumin), Jug r 2 (vicilin), or Jug r 3 (lipid transfer protein), are processed by professional antigen-presenting cells (APCs) and their constituent peptides are loaded onto Major Histocompatibility Complex (MHC) class II molecules, typically HLA-DR, DQ, or DP (WHO/IUIS Allergen Nomenclature Database; PMID: 25599184). These peptide-MHC (pMHCII) complexes are then presented on the APC surface to be recognized by specific T-cell receptors (TCRs) on CD4+ T helper cells (Janeway's Immunobiology). In allergic individuals, this interaction typically triggers a Th2-biased immune response, characterized by the secretion of IL-4, IL-5, and IL-13, leading to the production of allergen-specific IgE and subsequent mast cell degranulation (PMID: 30102974). Therapeutically, this complex is the primary target for allergen-specific immunotherapy (AIT), including oral (OIT) and peptide-based immunotherapy (PIT), which aim to reprogram the immune system toward tolerance (PMID: 31103434). By modulating the interaction between the walnut peptide-MHC complex and the TCR, these treatments seek to induce T-cell anergy, deletion, or the expansion of regulatory T cells (Tregs) to prevent systemic allergic reactions and anaphylaxis (PMID: 28212939).

Other names

Walnut allergen-HLA class II complexJug r peptide-MHC II complexWalnut-specific T-cell epitopeWalnut allergen-MHC II-TCR complex

Induction of immune tolerance through T-cell desensitization, anergy, or the expansion of regulatory T cells (Tregs) that suppress the Th2-mediated allergic response.