Lecture 10 Flashcards
where in the body do T cell precursors develop?
thymus
what makes up the thymic stroma?
epithelial cells, dendritic cells, and macrophages
what does it mean if a mouse is “nude”?
no thymus due to a defect in transcription factor important for terminal epithelial differentiation
regarding TCR’s the ____ and _____ chains have ___ segments wheras the _____ and _____ have __ segments
beta; delta; VDJ
alpha; gamma; VJ
what receptor ultimately drives T cell development?
Notch receptor
what makes a T cell double negative?
it lacks both CD4 and CD8 expression
what causes a thymocyte to become double positive?
beta, gamma, and delta rearrangements cause CD4 and CD8 upregulation
what is CD3 important for?
signal transduction
if a double positive thymocyte interacts with MHCII what gene is going to be upregulated?
CD4
if a double positive thymocyte interacts with MHCI what gene is going to be upregulated?
CD8
what happens after double negative thymocytes commit to T lineage?
beta genes are rearranged
in thymic selection, what is positive selection?
gives a thymocyte a survival signal if it bears receptors that can bind self-MHC molecules resulting in MHC restriction
in thymic selection, what is negative selection?
reduces autoreactivity by eliminating thymocytes bearing high affinity receptors for self-MHC or self-Ag
when does positive selection occur?
during the double-positive stage
what does AIRE stand for?
autoimmune regulator
what is the importance of AIRE?
need to be able to present self-antigens in the thymus from all parts of the body
what is the importance of negative selection?
to protect against autoimmunity
what cytokine causes the suppression of autoreactive T cells?
TG4B
