11. Autoimmunity and Tolerance

Question 1

Central T cell tolerance

Answer 1

Negative selection in the thymus: Getting rid of T cells that have too high affinity to self MHC

Question 2

Central B cell tolerance

Answer 2

Negative selection in the bone marrow: B-cells having too strong recognition of antigens will undergo apoptosis or receptor editing

Question 3

Peripheral tolerance

Answer 3

Immunological tolerance developed after autoreactive T and B cells mature and enter the periphery

Question 4

Treg cell effects (peripheral tolerance)

Answer 4

• Inhib. cytokines: TGFbeta, IL-10, IL-35 can suppress effector T cells
• Cytolysis: Treg can secrete granules containing Granzyme A/B and perforin …-> apoptosis
• Metabolic disruption: Involves secretion of IL-2, CAMP and adenosine

Question 5

What happens if an APC presents antigen with MHC to T cell without costimulatory molecules?

Answer 5

Lack of reaction (anergy)

Question 6

Immunological homunculus

Answer 6

Refers to the recognition of the most essential autoantigens of the body by protecting natural autoantibodies

Question 7

Genetic susceptibility for insulin dependent DM

Answer 7

Susceptibility molecule: No charge at position 57, groove is more open over position 9

Question 8

Natural autoantibodies produced by

Answer 8

B1 B cells

Question 9

Superantigens effect

Answer 9

They bind MHC and TCR from outside the peptide binding group -> may induce proliferation of a high number of T cell clones non-specifically

Question 10

Hashimoto thyroiditis

Answer 10

• CD4 T cell recruits autoreactive CD8 T cell and B cell

- Plasma cells and CTL induces apoptosis of thyroid cells -> hypothyroidism