Autoimmunity Flashcards
What are the 2 regions in a t cell and b cell receptor
Constant region
Variable region
Which region of the t/b cell receptor binds to the antigen
Variable region
What is the t cell response
T cell proliferation
Cytokine production
Help b cells
Cytotoxicty
What is the b cell response
Antibody production
Antigen presentation
What is the variable region produced of in the heavy chain
V
D
J
What is the light chain produced of
V
J
What is a problem that can happen by shuffling these genes
You can create an immunoglobulin or t cell that recognises its own self
What are the ways to stop t cells or b cells form recognises self cells
T cell tolerance
B cell tolerance
What happnes in central t cell tolerance
- Pre t cells emerge from the bone marrow and gro through the thymus
- Thymus carries out positive and negative selection
- Positive selection: when the t cell binds to something
- Negative selection: when the t cell bidns to something tightly it is killed
- When the t cell passess positive and negative selection it becomes a t naive cell
If the t cell during negative selection binds moderately what happens to it instead of being deleted
Becomes a T regular cell
What is the role of t reg cells
Have immunosupression molecules
Directly kill other immune cells
Why are t reg cell important
If t reg binds to a mhc that is expressing self peptide it activates t reg cells
What is another way of producting t reg cells
- Dendritic cell picks up self protein and displays it onto the MHC
- Naive cd4 t cell that recognises it becomes a induced t reg cell
Describe what happens in b cell tolerance
- In the bone marrow chains of immunoglobulin are made
- If the b cell cant present the immunoglobulin on the surface it will die of apoptosis
- The heavy chain and then the light chain rearranges which causes the intact immunoglobulin on the surface of the b cell
- The b cell is checked by positive selection is there is self reactivity
- If there is no self reactivity it is released as a transition b cell which becomes naive b cell in the lymph nodes
- If there is an autoreactive signal in the b cell, the chains are rearranged and check for autoimmunity
What is an autoimmune disease
A self directed inflammation caused by auto reactive t and b cell repsonse arising from a failure of immune tolerance to self antigens