T and B Cell Development Flashcards
Site of origin for B and T cells
Bone marrow
CD3
Multi-subunit complex associated with T cell receptor that isn’t antigen specific or variable
Transmits intracellular signals when T cell receptor is engaged
Steps of T cell development
- Hematopoietic stem cells travel from bone marrow to thymic cortex
- Double negative (CD4 and CD8 negative) T cells undergo T cell receptor gene rearrangement
- T cells become double positive (CD4 and CD8 positive)
- Positive and negative selection to become either CD8 or CD4 cells
- Negative selection in thymic medulla
- Naive T cells travel to peripheral tissues
Do T cells display allelic exclusion?
Yes- each T cell expresses only one receptor allele
T cell beta chains are made up of which fragments?
V (variable), D (diversity), J (joining), C (constant)
Steps of beta chain gene rearrangement
- D-J joining
- V-DJ joining
- C-VDJ joining
T cell alpha chains are made up of which fragments?
V (variable), J (joining), C (constant)
Which T cell chains rearrange first, alpha or beta?
Beta chains rearrange before alpha chains
What is the “antigen” being presented to new T cells during positive and negative selection?
Self-proteins
Positive selection
T cells that can bind self-MHC proliferate
T cells that fail to bind self-MHC undergo death by neglect
Negative selection
T cells that bind self-MHC too strongly are destroyed
Goldilocks principle with positive and negative selection
Want intermediate affinity for self-MHC: too much interaction or too little interaction is bad and leads to T cell death
Site of B cell development
Bone marrow
What cytokine is important for B cell differentiation?
IL7
Steps of B cell development
- Heavy chain rearrangement
- Light chain rearrangement
- IgM expression on cell surface
- IgD expression on cell surface
