T Cell Basics
This is the organ where T cells mature after originating from bone marrow stem cells.
What is the thymus?
This co-receptor binds to MHC Class I.
What is CD8?
This is the approximate percentage of thymocytes that successfully leave the thymus.
What is less than 5%?
This interaction provides "Signal 1" to a naïve T cell.
What is the TCR recognising the antigen-MHC complex?
Antigens processed via the endogenous pathway are presented on this MHC class to this T cell type
What is MHC Class I to CD8+ T cells?
This percentage of peripheral blood lymphocytes are T cells.
What is 80%?
This co-receptor binds to MHC Class II on helper T cells.
What is CD4?
This type of selection keeps T cells with moderate affinity for MHC
What is positive selection?
This interaction provides "Signal 2" (co-stimulation) to a T cell.
What is CD28 on the T cell binding to B7 (CD80/86) on the APC?
This CD4+ T cell subset primarily helps activate macrophages to kill intracellular microbes.
What is TH1?
T cell receptors can only recognise antigens in this form — short peptides bound to these molecules.
What are MHC molecules?
This accessory molecule pair (besides CD4/CD8) stabilises the APC–T cell interaction.
What are LFA-1 and ICAM-1?
This type of selection removes T cells that react strongly to self-antigens.
What is negative selection?
B cells present antigen to helper T cells on this MHC class.
What is MHC Class II?
This CD4+ T cell subset primarily helps B cells produce antibodies against extracellular parasites.
What is TH2?
This process generates the diversity of the TCR variable region.
What is V(D)J recombination?
This CD marker on T cells is the receptor for the B7 co-stimulator.
What is CD28?
This term describes the activation of naïve T cells on first encounter with antigen on a dendritic cell.
What is T cell priming?
This cytokine and its receptor are produced upon full T cell activation to drive proliferation
What are IL-2 and IL-2R?
CD8+ cytotoxic T cells release these two molecules to induce apoptosis in target cells.
What are perforin and granzymes?
These three components make up the T cell receptor complex.
What are the TCR, CD3, and ζ (zeta) chain?
This CD marker, expressed on activated T cells, B cells and macrophages, is the IL-2 receptor α chain.
What is CD25?
This cell type is the most effective at providing both signals to activate a naïve T cell.
What is the dendritic cell?
This happens to a T cell that receives Signal 1 without Signal 2.
What is failure to become fully activated (anergy)?
This is the key benefit of CD8+ T cell killing via apoptosis, compared to other mechanisms.
What is clearing the target cell without causing an inflammatory response?