Regulation of the immune response Flashcards
T & B cells generate
self-antigen receptors that must be destroyed or turned off
Regulation of adaptive immunity
- recognize & eliminate foreign invaders
- kill target cells
Tolerance
lack of immunity
Immature lymphocytes become tolerant to an antigen if they first met in fetal life. Observed in
chimeric calves
Central
-immature self reactive lymphocytes w/in thymus, bursa, or bone marrow die or alter their receptor specifity
Peripheral
mature lymphocytes that encounter self-antigens are turned off or suppressed by T reg cells
Chimera calves
fused placenta, born from same cow, NOT twins, cells migrate to eachother, grow inutero e/ contact from each other
- born with cells from other calf
- skin grafts will NOT BE REJECTED since they were in contact while maturing
What cells are more easily rendered tolerant: T or B cells?
T cells are more tolerant
Cells w/ non functional TCRs will undergo apoptosis
negative selection
Thymic epithelial cells
express many proteins from different tissues
AIRE= transcription regulator, autoimmune regulator
Positive selection
ensures that the cells that recognize self-MHC molecules survive
Recognize self antigens?
yes-apoptosis
no-negative selection
React w/ MHC?
moderately=positive selection
proliferation–> MHC restricted noneself reactive T cells
Very high or low dose of antigen cause
TOLERANCE
Moderate dose of antigens cause
antibody production
