elements of the adaptive immune system Flashcards
dendritic cells
DC are the most potent antigen presenting cell
they travel to the lymph node through the lymphatic vessels where T cells and B cells are activated and antibodies and cytotoxic T cells are released
antibody
only used in the adaptive immune system
cytotoxic T cells
need lots of them to kill infection and can kill virus infected cells and can encourage to kill cancer cells
what is an Antigen?
anything that has the potential to be recognised by the immune system
foreign antigens are anything from the outside
auto-antigen immune system - usually tolerant of auto- self antigen but may be recognised in autoimmune disorders
purpose of antigen uptake
clearance of pathogens (innate response)
for presentation to T cells (adaptive response)
MHC-1
presents endogenous (intracellular) antigens, expressed on all nucleated cells
MHC-2
presents exogenous (extracellular) antigen expressed only on antigen presenting cells
immuno-surveillence of antigen
peptides generated from proteins antigens are displayed on Major Histocompatibility (MHC) molecules
MHC/ peptide complexes can then be surveyed by antigen-specific cells
Endogenous antigens
peptides loaded onto MCH class 1 molecules for immune surveillance. viruses growing inside the cytoplasm and they go to the MHC-1 pathway
MHC-1 antigen processing
antigenic proteins are degraded to peptides in cytoplasm
peptides are imported into endoplasmic reticilum
peptide loading of MHC-1 takes place in the ER.
Exogenous antigens
peptides loaded only MHC class 2 molecules for immune surveillance.
phagocytosis of exogenous antigen
phagolysosome
destruction and loading in the lyzosome
MHC-2 antigen processing
antigenic proteins are degraded in acidic phagolysosome
peptide loading of MHC-2 takes place in the phagolysosome
