Adaptive Immunity Flashcards
Where do T lymphocytes originate from?
Stem cells in bone marrow
Mature in thymus
What is the function of T helper cells?
Regulate and activate immune cells
What cell surface protein do T helper cells express?
CD4
What is the function of cytotoxic T cell?
Recognise cells infected by intracellular pathogen
Induce apoptosis
Secrete TNF, perforin, Fas
What cell surface do cytotoxic T cells express?
CD8
How many polypeptides make up alpha beta T cell antigen receptor?
2
What does the T cell antigen receptor bind to?
MHC I or II on target cell surface
What MHC class do CD4 bind to?
MHC class II
What MHC class do CD8 bind to?
MHC class I
How do we generate unique specificity in T cell antigen receptors?
Alpha beta chain form antigen recognition site
DNA recombination
Which cells express MHC I?
All cells
What are the 3 gene loci that code for MHC I?
HLA-A
HLA-B
HLA-C
Which cells express MHC II?
Antigen presenting cells: macrophages & dendritic cells
Activated B and T cells
What are the 3 gene loci that code for MHC II?
HLA-DR
HLA-DP
HLA-DQ
What are naive T cells activated by?
Mature dendritic cells
Where does T cell activation happen?
Lymph nodes
What are the differences between MHC I and II antigen processing?
MHC I: antigen uptake, processing and transported by TAP
MHC II: endocytosis and digestion
Which interleukins are associated with Th1?
IL-2
IFNy
Which interleukins are associated with Th2?
IL-2
IL-4
IL-5
IL-13
How is T cell immune response switched off?
Stimulating receptors CD28 and CD4 replaced with inhibitory receptors CTLA4 and LAG3
Apoptotic receptors
How does T cell selection work?
Positive and negative selection in the thymus
Must not be self reactive
Where exactly does positive and negative selection happen?
Positive in thymus cortex
Negative in thymus medulla
