Immunology

Question 1

Hashimoto thyroiditis what is thought to be the main cause of thyroid destruction?

A. CD8 cells
B. Ab TG
C. Ab TG and TPO
D. histiocytes

Answer 1

A. CD8 cells

Ab used to detect hashimoto are likely minor players in the destruction of thyroid cells.

Question 2

What MHC type is associated with hashimoto specifically?

Answer 2

HLA class II DR3,5

Question 3

What are the steps leading to the breaking of immune tolerance in Hashimoto thyroiditis?

Answer 3

Ag (thyroid, viral, or cross reactive) CD4 and Th1 activation, IFN-gamma, activation of CD8 cells

AND

Ag, CD4+ with Tfh cells (IgG, IgA), B-cells , anti-TSHR, TPO, and TG

Question 4

What are the steps leading to the breaking of immune tolerance in Graves disease?

Answer 4

Viral Ag cross reactive with TSHR, Tfh secrete IL4,6, B-cells produce anti-TSH antibody

Question 5

Which is a larger titer 1:160 or 1:4000?

Answer 5

1:4000 because it had to be diluted that much before no trace elements were found.

Question 6

Briefly describe pos, neg selection and death by neglect

Answer 6

Pos selection in the thymus-weak binding of MHC I and II
Neg selection is strong binding of MHC I and II
Death by neglect when no binding of either (fail to get signals to survive)

Question 7

What role does CTLA-4 play in T-cell regulation?

Answer 7

CTLA-4/ CD152 down regulates T-cells