Antigen presentation

Antigen presentation is the display of peptide fragments bound to major histocompatibility complex molecules on cell surfaces, where T-cell receptors can recognize them.

Major histocompatibility complex: A family of cell-surface proteins that binds antigen fragments and presents them to T cells. MHC molecules are the platforms that carry displayed peptides.
Peptide–MHC complex: A complex formed when an antigen-derived peptide binds an MHC molecule. This is the molecular unit displayed for T-cell inspection.
Dendritic cell: A professional antigen-presenting cell that activates naïve T cells. Dendritic cells efficiently display antigen and provide signals that initiate T-cell responses.
MHC class I: An MHC molecule expressed by nearly all nucleated cells that presents peptides mainly to CD8 T cells. This pathway typically displays peptides derived from proteins inside the presenting cell.
Proteasome: A protein complex that degrades proteins into peptides, among other roles. It generates many intracellular peptides presented through MHC class I.
T-cell receptor: A receptor on T cells that recognizes specific peptide–MHC complexes. Its binding to displayed peptide–MHC initiates antigen-specific recognition.
Cancer immunotherapy: Treatments that harness or modify immune responses to control cancer. Tumor peptide display can expose cancer cells to T-cell attack and guide immunotherapy.
MHC class II: An MHC molecule expressed chiefly by professional antigen-presenting cells that presents peptides mainly to CD4 T cells. This pathway typically displays peptides acquired from outside the presenting cell.
TAP transporter: A membrane protein complex that transports cytosolic peptides into the endoplasmic reticulum. TAP supplies peptides for loading onto MHC class I.
CD4: A T-cell surface protein that binds MHC class II and supports helper T-cell activation. CD4 stabilizes recognition of class II-presented peptides.

Linked from 30 pages