Autoimmunity Basics Flashcards
How do T-reg cells function to dampen immune response
CTLA4 on CD4+ Treg cells
binds B7 so CD28 cannot bind that
binds up costimulatory molecule to dampen immune response
How do T-cells directed against self in periphery undergo anergy
TCR binds MHC
but no costimulatory molecule (because no inflammation)
undergoes anergy
Positive vs negative selection of T-cells
positive: in cortex, needs to bind MHC I or II
negative: in medulla, cannot bind self on DC or MED
Where does T-cell negative selection occur
in medulla
ie toward the inside, b/c moves to center of node on the way out into circulation
AIRE mutation
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
Why do women get autoimmune diseases more than men
estorgen reduces apoptosis of self-reactive lymphocytes
Why are autoimmune diseases very often relapsing-remitting
because antigen is always present
Epitope spreading
*reason many autoimmune diseases have overlapping Sx
autoimmune destruction leads to spilling of more self-antigens
Ab formed to there –> epitope spreading