B & T cell Flashcards
Where do B cell mature?
bone marrow
Where do T cell mature?
thymus
What is the difference between primary + secondary lymphoid organs?
- Primary: where they mature
* Secondary: where the immune system is activated
How is B immunoglobulin like- amount of chains + binding site?
2 heavy + 2 light
2 binding site
How is T immunoglobulin like- amount of chains + binding site?
1 alpha + 1 beta
1 binding site
What is purpose of thymic education?
- teaches it to only recognize peptide bound to MCH (MHC restricted T cell)
- teaches it not to attack anything in body (self reacting T cell not made)
When is most T cells made and why?
childhood –> when thymus is biggest
What is a thymus defect?
DiGeorge –> defect in chromosome 22 –> no/small thymus –> No T cell + B cell produced but can’t make antibodies
How does a T cell develop?
At thymus cortex: T cell with CD4+ & CD8+ made
Thymus medulla: positive + negative selection
- MHC 1 –> CD8+
-MHC 2 –> CD4+
Can be effector/ naiive T cell.
Naiive: go to peripheral lymphoid organ (doesnt encounter antigen)
effector: inflammation (does encounter antigen)
Where does negative selection happen in thymus for T cell development? And what does that mean?
thymus medulla - MUST BE binding to peptide to receptor (MHC) is the perfect amount
< or > –> negative selection
What is positive selection?
T cell survive –> correct TCR + MHC response by cortical epithelial
What is negative selection?
T cell die –> incorrect/ strong TCR + MHC response by thymic epithelial
What is CD is needed for T cell signalling?
CD3
How do T cell die?
apoptosis
Where does B cell development start + mature?
start: bone marrow
mature: peripheral lymphoid organs
