Immunology 8 Flashcards
Unlike B-cells, T-cells undergo very little maturation in the ?
bone marrow
After stem cells “choose” to become lymphoid progenitors, those progenitors divide under the influence of
IL-7
T cells need to travel to the ? to develop function T-cell receptors (TCR)
thymus
where is the thymus located
superior to the heart and anterior to the great vessels
thymus is largest or smallest prior to puberty?
largest
the thymus is divided into ?
cortex and medulla
what does double negative mean?
the T-cell precursors do not express CD8 or CD4
when DN cells commit to a T-cell lineagethey are known as ?, these cells are mostly found in the ?
DN3 cells
cortex of the thymus
DN cells first rearrange the ? of the TCR, If this is done correctly, then proliferation continues known as ?. If the beta chain is useless, the ?
beta chain
DN4
cell dies
After the beta chain is rearranged and done correctly, the ? of the TCR is then shuffled.
alpha chain
After both TCR chains have been recombined, the developing T-cell expresses both CD4 AND CD8 -> ?
double positive (DP)
DP cells will recombined with TCRs sample…
thymic epithelial cells HLA
If DP cells has very low affinity interactions to thymic epithelial cells HLA ->
death of the DP T-cell
If DP cells has medium-low affinity interactions to thymic epithelial cells HLA ->
survival of the DP T-cell
If DP cells has very high affinity interactions to thymic epithelial cells HLA ->
death of the DP T-cell
DP cells that have been positively selected and have survived negative selection then ?
“make a choice”
The DP cell with its useful TCR will ? to see if the CD8 or CD4 co-receptor interacts better with the medullary TECs
“test”
ultimately, at the end of T cell development, T cells express only ? or ?
CD4 or CD8
what is the rationale for positive selection when TCR has a “low-medium” affinity for a thymic epithelial cell’s (TEC) HLA bound to self-antigen, it is allowed to survive
the TCR is capable of interacting with an HLA molecule, but is unlikely to recognize self
what is the rationale for negative selection when TCR has a “high” affinity for a thymic epithelial cell’s (TEC) HLA bound to self-antigen, it is allowed to survive
this is T cell with a TCR that recognizes self – it should not be allowed to survive
what is a transcription factor-like protein that binds with a wide range of other transcription factors and activates them for central tolerance
AIRE
CD4+ Treg cells polarized by ?
interaction with an APC and presence of high circulating levels of TGF-B
what is expressed by helper T-cells, binds to B7 with higher affinity than CD28
CTLA-4
Binding of CTLA-4 to B7 (CD80/CD86) molecules on APCs usually renders the CD4+ cell ?
anergic
