Peptide-Major Histocompatibility Complex Class II Complex (pMHC-II)

The peptide-major histocompatibility complex class II (pMHC-II) complex is a molecular assembly formed when a major histocompatibility complex class II (MHC-II) molecule binds an antigenic peptide. This complex is essential for the adaptive immune response, as it enables antigen-presenting cells (APCs)—such as dendritic cells, macrophages, and B cells—to display processed extracellular antigens on their surface for recognition by CD4+ T lymphocytes. The MHC class II molecule is a heterodimer composed of an α-chain and a β-chain, forming a peptide-binding groove that accommodates peptides typically 13–25 amino acids in length. Presentation of exogenous antigens via pMHC-II is crucial for activating CD4+ helper T cells, which coordinate immune responses.

Other names

MHC-II peptide complexpMHCIIMHC class II peptide complex