T-cells Flashcards
Signal transduction complex in all T lymphocytes
CD3
CD4+, CD8-, TCR+
Helper T cell in circulation: NOT in thymus
CD4-, CD8+, TCR+
Cytotoxic T cell in circulation: NOT in thymus
CD4-, CD8-, TCR+
Not Possible- a coreceptor needs to be present before TCR is expressed
CD4-, CD8-, TCR-
Is possible of a T-lymphocyte that leaves the bone marrow for the thymus to not have coreceptor or to have not yet rearrange variable domain for TCR.
**If TCR+ there must be a coreceptor expressed
MHC Class I antigens are recognized by
CD8
MHC class II antigens are recognized by
CD4
Adhesion molecule that mediates attachment of lymphocytes and APC
CD2 aka LFA-2
Produced by T-cell to increase proliferation of T-cells in the periphery
IL-2
Describe a T-cell receptor
Membrane bound Alpha,Beta or Delta, Gamma heterodimer
Refers to the recognition of MCH I or MCH II by double positive CD4+, CD8+ thymocytes
Positive Selection
What location would you most likely find gamma/delta
T-cells?
They migrate to respiratory organs, skin, and peritoneal cavity
The adaptive immune response has to be turned on and off. This is done by the competing of what?
Competing of CTLA-4 (found exclusively on CD4 and CD8) with CD28 for the binding of B7 on the B-cell
What expresses high-affinity trimeric IL-2Ralphabetagamma
Ag-activated CD4+ and Ag-activated CD8+
What is the fate of a T-cell that has high affinity for self-MHC?
Deletion in the thymus via induced apoptosis
When a resting naive T-cell engages its specific MHC/peptide complex displayed on the surface of a fibroblast what happens to the T-Cell?
It becomes anergic
What component of the TCR receptor complex is responsible for signal transduction?
CD3
What type of structure is the TCR
A heterodimer consisting of an alpha chain and beta chain…….or a gamma chain and delta chain
What segment is not present in the alpha chain gene of TCR?
Diversity (D)
The T cell receptor alpha chain genes do not posses D gene segments, although the delta chain genes do.
Any alpha chain rearrangement leads to the loss of the delta chain gene segments.
What is the percentage of human peripheral blood T-cells bearing a gamma/delta T-cell receptor?
1-5%
