Autoimmunity Basics

Question 1

How do T-reg cells function to dampen immune response

Answer 1

CTLA4 on CD4+ Treg cells
binds B7 so CD28 cannot bind that
binds up costimulatory molecule to dampen immune response

Question 2

How do T-cells directed against self in periphery undergo anergy

Answer 2

TCR binds MHC
but no costimulatory molecule (because no inflammation)
undergoes anergy

Question 3

Positive vs negative selection of T-cells

Answer 3

positive: in cortex, needs to bind MHC I or II
negative: in medulla, cannot bind self on DC or MED

Question 4

Where does T-cell negative selection occur

Answer 4

in medulla

ie toward the inside, b/c moves to center of node on the way out into circulation

Question 5

AIRE mutation

Answer 5

leads to multiple endocrinopathies
*some antigens (endorine) depend on AIRE to be presented in node
*this is responsible for neg selection
*no neg selection = damage because not weeded out
parathyroid, adrenal, recurrent Candida infections

Question 6

Why do women get autoimmune diseases more than men

Answer 6

estorgen reduces apoptosis of self-reactive lymphocytes

Question 7

Why are autoimmune diseases very often relapsing-remitting

Answer 7

because antigen is always present

Question 8

Epitope spreading

Answer 8

*reason many autoimmune diseases have overlapping Sx
autoimmune destruction leads to spilling of more self-antigens
Ab formed to there –> epitope spreading