Adaptive Immunity Flashcards
What are the 3 materials that compose blood
Plasma
Leukocytes (white blood cells)
Red blood cells
What are the most potent antigen presenting cells
Dendritic cells
First on scene to sample antigen
Have a powerful role of antigen uptake and presentation
Outline Dendritic cell involvement in sampling and presentation
Dendritic cells present in major organs
They phagocytise antigen and process it down to peptides
They migrate from organs to draining lymph node
They present peptides on MHC to other white blood cells (T cells)
What is unique about the peptide constituents of phagocytised antigens
They are unique sequences of amino acid code that let the body know something foreign is invading
Summarise dendritic cell involvement in adaptive immunity
Dendritic cells present peptides on MHC to T cells (in lymph nodes or spleen)
CD4 T cells help B cells make antibody
CD8 T cells become cytotoxic and kill virus infected cells and cancer cells
What is antigen
Anything that has the potential to be recognised by the immune system
Foreign antigen - anything from outside (transplants, pathogens, some chemicals)
Auto/self antigen - immune system normally tolerant of self antigen. May be recognised in autoimmune disorders
What is the purpose of antigen uptake
Clearance of pathogens - sterilising immunity (no bugs left)
For presentation to T cells for adaptive immune response
How long ago did phagocytes evolve
500 million years ago
Evolved to keep remnants of pathogens and display these to other cells of the immune system
What immunity do invertebrates (insects, spiders, jellyfish) have
Innate only
What immunity do vertebrates have
Both innate and adaptive
What vertebrates have an altering type of adaptive immunity
Jawless fish. Adaptive system is based on different structures
What is MHC 1
MCH 1 presents endogenous antigen. Expressed on all uncleared cells
What is MHC 2
MHC 2 presents exogenous antigen. Expressed only on antigen presenting cells
Outline MHC 1 antigen processing
Antigen proteins are degraded to peptides in cytoplasm (protease enzymes)
Peptides are imported into endoplasmic reticulum
Peptides loaded onto empty MHC 1 occurs in ER
Peptide containing MHC 1 exocytosed onto cell membrane surface
Outline MHC2 antigen processing
Antigenic proteins are degraded in acidic phagolysosome
Peptide loaded into empty MHC 2 in phagolysosome
MHC 2 peptide complex exocytosed to cell surface
