Exam II - T Cells Flashcards
Of the profesional APCs, the most potent activators of TH cells is:
mature dendritic cells
Helper T cells respond only to:
processed antigen
Antigenic classification based on the different specific sugars of bacterial lipopolysaccharides:
O antigen
Also known as naive T cell:
Pre-T cell
This organ contains aggregates of lymphocytes in the form of lymphoid follicles
Spleen
This mitogen nonspecifically stimulates T cell mitosis:
Concanavalin A
(p 105)
Somatic mutations in these immunoglobulin genes result in the secretion of antibody with increased affinity for its antigen, ie, affinity maturation:
variable gene regions
Terminal deoxynucleotidyl transferase (TdT) contributes to the junctional diversity of T cell and B cell antigen receptors by catalyzing the addition of these nucleotides to the junctions between rearranged V, D, and J gene segments.
N-region nucleotides
Lysosomal protein that sequesters free iron in phagocytes, an event that impedes bacterial replication in the phagocyte
lactoferrin
Activates the extrinsic cellular apoptotic pathway:
Fas ligand (FasL)
Specialized cell that delivers luminal antigen to Peyer’s Patches:
M (microfold) cell
Causes lysis of antigen-bearing target cells:
Cytotoxic T cell (TC; CD8+)
Helps B cells produce antibodies to protein antigens:
Helper T cell (TH; CD4+)
functions to recognize the α domain of class I MHC molecules to enable cytotoxic T cells to bind to target cells:
CD8 (TCR coreceptor)
binds to the β2 domain of the class II MHC molecule on the surface of professional APCs:
CD4 (TCR coreceptor)
Also known as LFA-1:
CD11aCD18
Binds T cells to CD54 molecules (ICAM-1) on APCs and target cells:
CD11aCD18 (also known as LFA-1)
Constitutively-expressed membrane receptor for co-stimulatory signals (signal 2):
CD28
Recombination-activating genes 1 and 2 (RAG1 and RAG2) are only found where?
T and B lymphocytes
RAG1 and RAG2 are only active only in:
RAG1 and RAG2 are only active only in developing lymphocytes
Which is rearranged first: α chain genes or β chain genes?
β chain genes rearrange first
Which genes occur at the α locus?
- variable region genes (Vn)
- joining region genes (Jn)
“α-male gets all the VeeJay”
Which genes occur at the β locus?
- variable region genes (Vn)
- diversity region genes (Dn)
- joining region genes (Jn)
N-region nucleotide addition involves which enzyme?
terminal deoxynucleotidyl transferase (TdT)
major co-stimulator for TH2 cells
Interleukin-1
(TH1 cells lack IL-1 receptors and do not repond to IL-1)
T Cell receptor for B7 proteins:
CD28
These cells are able to respond to peptide-MHC complexes displayed on APCs that lack the co-stimulatory B7 molecule:
Effector TH Cells
Binds to CD40 on macrophages and B cells and activates them:
CD40L
What are the 3 types of effector T cells?
CD4+ TH1 and TH2 cells, and CD8+ T cell
Name a T Cell receptor for co-stimulation constitutively expressed on T cells. What is its ligand?
CD28; B7
Which cytokines lead to differentiation into TH1 and TH2?
IL-12 (TH1 via T-Bet) and IL-4 for TH2 (GATA-3)
What are the major cytokines produced by TH1?
IL-2, IL-12, IFN-gamma
What are the major cytokines produced by TH2?
IL-4, IL-5, IL-10
Produced in response to helminth parasites and other pathogens; causes proliferating CD4+ cells to differentiate into TH2 cells:
Interleukin-4
What are the 2 criteria for T cell selection?
Self MHC restrcition & self tolerance
Do all T cells need co-stimulatory signal?
No, just naive T cells.
Effector and memory cells do not require co-stimulatory signal
Why are mature dendritic cells the most potent activators of naive TH cells?
they constitutively express MHC molecules and co-stimulators
Which hypervariable region displays the most diversity?
CDR3
LFA-1 binds T cells to ____________ on APCs and target cells
LFA-1 binds T cells to CD54 molecules (ICAM-1) on APCs and target cells
Where are T cells produced?
thymus
