Immune Tolerance Flashcards
What is immune tolerance ?
A mechanism used by the immune system to prevent the immune system attacking self tissue
What are the two types of tolerance in B cells ?
Peripheral and central
What is central tolerance ?
B cells that recognise self antigens undergo apoptosis
Where does it occur ?
Bone marrow
What is peripheral tolerance ?
When auto-reactive B cells escape death in the bone marrow and then declared non responsive in the peripheral lymphoid tissue
Do T cells undergo tolerance ?
Yes but they just revive 2 signals
When does signal 1 occur ?
By CD3 after antigen recognition
When does signal 2 occur ?
By CD28 after interaction with B7 on APC
What happens if a T cell receives signal one without 2?
T cell is non responsive as this ensures that T cells are only activated by a professional APC
What is tolerance T cells known as ?
A mechanism called suppression which involves regulatory T cells
Example ?
pancreas specific antigen
Why?
It T cell escaped deflation the T cell would not be active aged by pancreatic cell as it couldn’t deliver signal 2
