91401 Lecture Notes - Lecture 3: Cytotoxic T Cell, Clonal Selection, Mhc Class I
Document Summary
T cells recognise mhc* + peptide displayed on cell surface. Tcr recognize peptide + mhc -if mhc + peptide is the right shape" then a t cell is activated (foreign antigens) If mhc + peptide is the wrong shape" then there is no activation (self antigens) ; Endogenous pathway: mediated by mhc-i, antigens arise from the cytoplasm (viral antigens are common, transporters associated with antigen processing (tap) transports small cytosolic peptides into the lumen of the endoplasmic reticulum (er) cd8+ cytotoxic t cells are activated. Exogenous pathway: mediated by mhc-ii cd4+ helper t cells are activated, antigens are extracellular in origin (phagocytosis) Cd4 t cells orchestrate adaptive immune response monitor extracellular space; cd8. T cells monitor nucleated cells for presence of intracellular antigens. Conserved anchor residues: peptides that bind a given mhc variant have the same or very similar amino acid residues at several positions, which fit pockets (lined by polymorphic amino acids) in the mhc peptide binding site.
