T Cell Development, Receptor Repertoire Selection And CD4/8 Lineage Commitment Flashcards
What does CD stand for in CD4/8?
Cluster of differentiation
Where do double negative T cells appear?
In the foetus
What type of T cells are favoured during early foetal development?
Gamma delta T cells
Do gamma delta T cells recognise the MHC protein?
No
What do gamma delta T cells play a role in?
Cancer surveillance
What does T cell development involve?
The sequential generation, assembly and testing of the newly rearranged TCR
What does a double +ve thymocyte need to progress to the single +ve stage?
Functional TCR alpha chain rearrangement CD4 and MHC II (-> CD4+) CD8, MHC I and TAP (-> CD8+) ERK signalling Calcineurin signalling
What is the initiation process of apoptosis?
Interaction between FAS ligand and FAS -> reaction cascade -> caspase 8 -> caspase cascade -> cell death
What can happen to a double +ve thymocyte?
Bind to MHC II (-> CD4+)
Bind to MHC I (-> CD8+)
Death by neglect
Negative selection
What are MHCs called in humans?
Human leukocyte antigens
Where are MHC-IIs expressed?
Thymic medullary stromal cells and high levels on APCs
What happens if the binding is too strong to self T cells?
The cell is reprogrammed for apoptosis
What does negative selection of T cells ensure?
Self-reactive cells are removed
Why are self Tcells removed?
They may cause autoimmunity
What is negative selection determined by?
Affinity of TCR for presented self peptide
