Allergen-derived peptide-Major Histocompatibility Complex class II complex (pMHCII) (pMHCII)

The allergen-derived peptide-Major Histocompatibility Complex (MHC) class II complex is a fundamental immunological structure formed on the surface of antigen-presenting cells, such as dendritic cells and B cells (Janeway's Immunobiology, 2016). This complex consists of a short, linear peptide fragment derived from an allergen (e.g., Fel d 1 from cats or Amb a 1 from ragweed) bound within the groove of an MHC class II molecule. The primary biological function of this complex is to present the allergenic epitope to the T-cell receptor (TCR) of CD4+ T helper cells, which in allergic individuals typically initiates a Th2-mediated inflammatory response (Larche, M., 2007, Nature Reviews Immunology). In the context of therapeutic development, this complex is the target of peptide-based allergen immunotherapy (PIT), where synthetic peptides are designed to bind MHC II and modulate T-cell activity without triggering IgE-mediated mast cell degranulation (Worm, M., et al., 2017, Allergo Journal International). By engaging the TCR in the absence of traditional inflammatory signals, these drugs aim to induce immune tolerance through the expansion of regulatory T cells (Tregs) and the induction of T-cell anergy (Patel, D., et al., 2013, J Allergy Clin Immunol). This approach represents a shift from symptomatic treatment to disease modification by directly addressing the underlying T-cell dysregulation in allergic diseases (Sabatos-Peyton, C.A., et al., 2010, Curr Opin Immunol).

Other names

Peptide-MHC II complexAllergen-MHC II complexpMHCII complexMHC class II-peptide complex

Induction of T-cell anergy, deletion of allergen-specific Th2 cells, and promotion of regulatory T-cell (Treg) differentiation to suppress allergic inflammation.