W21-L6: Self, Non-self discrimination Flashcards Preview

Matt's Block 06 - Neuro block > W21-L6: Self, Non-self discrimination > Flashcards

Flashcards in W21-L6: Self, Non-self discrimination Deck (23):
1

What is B cell Central Tolerance?

• Deletion
• Anergy

2

What is B cell Peripheral Tolerance?

Need 2 signals for the mature B cell to respond and survive

• Ignorance/Anergy/death (Lack of co-stimulation/T cell help)

3

T/F
B cell tolerance is more efficient than T cell tolerance

False

4

Where does T cell development occur?

Thymus

5

Double positive (DP) thymocytes undergo which selection processes following the expression of a TCR?

1. Positive selection-thymocytes that express TCRs capable of recognising self-MHC are selected to survive

2. Negative selection–removal of immature lymphocytes that have strong reactivity to self peptide

6

What controls expression of tissue specific antigens?

AIRE genes

7

What do defects in AIRE lead to?

failure of negative selection for some antigens, and result in autoimmunity

8

What is T cell central tolerance?

Involves immature/developing lymphocytes and occurs in primary lymphoid organs

• Deletion
• Selection of Tregs

9

What is T peripheral central tolerance?

Involves mature lymphocytes and occurs in secondary lymphoid organs, and peripheral tissues

• Deletion
• Anergy
• Ignorance
• Regulation

10

What two signals are required for activating naive T cells?

1. TCR-peptide MHC interactions

2. Co-stimulation

11

Without co-stimulation, T cells become...

anergic

12

What are iTregs?

derived following activation of naïve CD4 T cells in the presence of TGF ß

13

What do iTregs secrete and express?

Secrete immunosuppressive cytokines - IL-10 and TGF ß, Express CTLA4 and inhibit co-stimulation

14

How does CTALA4 work?

Binds B7 on APC more avidly than CD 28 on niave T cells and delivers inhibitory signals to activated T cells

15

What are 3 key components of autoimmunity?

1. Genetic susceptibility
2. Environmental
3. Loss of self-tolerance

16

What are the two types of autoimmune disease?

1. Organ-specific: Confined to particular organs or cell types and the
antigens recognized are organ specific

2. Systemic: Multiple tissues of the body are targeted and the antigens recognized are more ubiquitous

17

What are some diseases related to B cell autoimmunity?

1. Graves disease (stimulating Ab)

2. Myasthenia Gravis (inhibitory Ab)

3. SLE (immune complex deposition)

18

What are some diseases related to T cell autoimmunity?

1. Insulin dependent diabetes mellitus (IDDM)

2. Multiple sclerosis (MS)

19

Type 1 insulin dependent diabetes mellitus is characterised by?

autoimmune destruction of pancreatic β-cells, characterised by infiltration of lymphocytes, weak autoantibody response, T cell reactivity to islet proteins

20

What genes are more frequently found in Type 1 insulin dependent diabetes mellitus?

HLA DR3-DQ2 and DR4-DQ8

21

Multiple Sclerosis is characterised by?

CD4 T cells specific for myelin antigens promote an inflammatory response and degrade the myelin sheaths covering nerve axons

22

Which genes are associated with multiple sclerosis?

HLA-DR15 and HLA-DQ6

23

What is Molecular mimicry?

• Antigens from pathogen are similar in shape to autoantigens

• Able to cross react with autoreactive T cells/B cells

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