Major histocompatibility complex–peptide complex on dendritic cells (MHC–peptide complex)

The **major histocompatibility complex–peptide complex on dendritic cells** is the molecular assembly formed when dendritic cells (professional antigen-presenting cells) load antigenic peptide fragments onto their MHC molecules—MHC class I or MHC class II. This complex is then trafficked to the cell surface, where it interacts with T cell receptors (on CD8^+^ for class I and CD4^+^ for class II) to trigger adaptive immune responses, including cytotoxic, helper, and regulatory pathways. MHC–peptide complexes are central in discriminating self from nonself, and their presentation governs immunity, tolerance, and autoimmunity. Therapeutics engage these complexes indirectly by augmenting antigen presentation, modulating immune activation, or engineering vaccine approaches to enhance recognition of pathogens or cancer cells.

Other names

MHC–peptide complexPeptide–MHC complexMHC–antigen complexMHC class I–peptide complexMHC class II–peptide complexpMHC (peptide–MHC complex)

Drugs do not directly bind the MHC–peptide complex but modulate its function by: - Blocking costimulatory signals (CTLA-4, PD-1/PD-L1 inhibitors) - Enhancing antigen presentation (use of cytokines, DC maturation agents) - Loading specific peptide antigens (cancer vaccines, personalized immunotherapy)