5 T Cell Diversity and Development Flashcards
Where is a T cell made?
Bone Marrow
Where does a T cell mature?
Thymus
Where does a T cell live?
Secondary Lymph
What does a T cell derive from?
Common lymphoid precursor
What type of single antigen is recognized by a T cell?
peptide antigen in context with MHC
What cells does a T cell help activate?
Macrophage
CD4 Helper T cell
What are the 2 types of T cell lineage TCRs?
AB and yD
What is different about AB T cells?
Thymic development
Peptide recognized
MHC restricted
What is different about yD T cells?
Mucosal epithelium location
Lipid recognized
Non thymic development
Non-MHC restricted
What do CD3 surface markers do?
Signal transduction
What relies on CD3?
T cell activation
What is an ITAMs?
immunoreceptor tyrosine-based activation motifs in CD3 TCRs
What are CD4 and CD8?
Coreceptors for TCRs
All mature T cells have one or the other
What are structural differences between CD4 and CD8?
CD4 is a single chain
CD8 is a heterodimer
What MHC class does CD4 recognize?
MHC II
What MHC class does CD8 recognize
MHC I
What antigen type is the MHC II pathway used for?
Extracellular pathogens
What antigen type is the MHC I pathway used for?
Intracellular pathogens
What is CD28 used for?
Costimulation of T cells
Binds B7 molecules from APCs
What is Fas ligand used for?
Apoptotic pathway
What is the meta organization of the thymus?
Cortex
Medullary region
Where does positive T cell selection occur?
Thymus cortex
Where does negative T cell selection occur?
Medullary region
Hassal’s corpuscle
What is the first step in T cell maturation in the thymus?
MHC is presented by cortical cells
What is the second step in T cell maturation in the thymus?
Somatic recombination
What is the overview of T cell maturation?
Somatic recombination
Positive selection
Negative selection
What is the first chain of the TCR to begin adapting to maturation signals?
Beta chain genes
What happens in T cell maturation after AB chain recombination?
Expression of CD3, then CD4 aaaand CD8
When CD4/8 is produced on T cells, what occurs?
Positive selection of MHC I/II in the cortex
What is downregulated as the T cell moves into the medullary region?
The unused CD4/8
What is destroyed in the medullary region?
Self recognizing T cells
How does a T cell become a yD TCR?
If y or D are expressed first
How does a T cell become a AB TCR?
- B chain expressed
- Invariant chain (pTalpha) transcribed and binds
- Pre-T cell receptor combines with the CD3 complex
- AB TCR rearrangement (full A chain made)
- CD4/8 production
- CD4/8 selection
- Migration to 2* lymph
What occurs in alpha chain gene recombination ?
Random
- VJ region brought together
- Transription
- C region spliced to be proximal
- Translation
What occurs in B chain gene recombination?
Random
- VDJ region joined
- Transcription
- C region spliced to be proximal
- Translation
What T cell tumor would express CD34?
T cell tumor of Bone Marrow stem cell origin
What T cell tumor would express CD10,19, 20?
T cell tumor of Thymus progenitor cell origin
What T cell tumor would express CD1?
T cell tumor of Thymus developing cell origin
What T cell tumor would express CD3, CD4/8, or TCRs?
T cell tumor of peripheral origin from mature T cell
