T-Cell Biology

Question 1

CD4+ cell info

Answer 1

65% of T cells in blood

Can differentiate into Th1,2, or 17

middlemen of adaptive immune response

interact with MHC class II

Question 2

CD8+ cell info

Answer 2

release cytolytic enzymes like granzyme and perforin to destroy cells via apoptosis

target virally infected cells and tumor cells and interact with MHC class 1

Question 3

places of T lymphocyte maturation

Answer 3

bone marrow to thymus to blood/periphery

Question 4

names of T lymphocyte stages of maturation

Answer 4

stem cell (marrow) (double negative b/c no cd4 or 8)
pro-T (thymus)
Pre-T (thymus)
double positive (Cd4 and cd8) (thymus)
Single positive (one of cd4/8) (thymus)
naive mature T cell (periphery)

Question 5

double negative thymocytes importance

Answer 5

no cd4 or 8 but up regulate the production of the membrane glycoproteins which is followed by TCR gene arrangement and then generation

Question 6

positive selection in thymus

Answer 6

double positive thymocytes are tested to see if they will bind self MHC class I and II molecules…those that bind with low or moderate affinity are allowed to keep on developing

those that do not recognize the MHC I or II molecules or bind them too tightly will be destroyed

Question 7

negative selection in thymic education

Answer 7

medulla thymic epithelial cells then ask the developing T lymphocytes if they recognize self antigens…those that bind any self peptide with high affinity will be destroyed

leads to tolerance of our own proteins…

Question 8

1st signal in T cell binding

Answer 8

this is signal when the TCR successfully binds to the MHC molecule and the peptide presented

Question 9

2nd signal in T cell binding

Answer 9

complete T cell activation…is the interaction of CD28 from the T cell and B7 from the antigen presenting cell surface

Question 10

anergism

Answer 10

when T cell does not have second signal in pathway…no CD28 or B7 activation …the T cells are no longer responsive to antigen stimulation

“mechanism of self tolerance induction”

Question 11

CD3 proteins

Answer 11

proteins with long cytoplasmic tails that are associated with the TCR complex

Question 12

immunoreceptor tyrosine based activation motifs (ITAMs)

Answer 12

on ends of CD3 proteins in the TCR complex, phosphorylated once the TCR has bound

Question 13

importance TCR/MHC complex and CD28 for IL-2

Answer 13

drive initiation (complex) and expression (CD28)

Question 14

CD25

Answer 14

this is the IL-2 receptor and when IL-2 binds the CD25 it promotes cell division

Question 15

CD40 ligand and receptor

Answer 15

ligand found on helper T cell (CD4) and the receptor on a macrophage…it enhances the activation of the macrophage

receptor can also be found on a B lymphocyte and will lead to antibody secretions

Question 16

dendritic cells role in adaptive immune response

Answer 16

the dendritic cells are in charge of telling the CD4 helper cells what cytokines they are going to make…

if the CD4 cells are the quarterback then the dendritic cells are the coach

Question 17

Th1 Cell cytokines

Answer 17

IFN-gamma, TNF-alpha

Question 18

Th1 cell immune reactions

Answer 18

activate macrophages, increase IgG production, blocks Th2 cell development

Question 19

Th1 cell host defenses

Answer 19

intracellular microbes, mainly bacterial

Question 20

Th2 cell cytokines

Answer 20

IL-4,5,13

Question 21

Th2 cell immune reactions

Answer 21

mast cell, eosinophil activation, IgE production, macrophage activation

Question 22

Th2 cell host defenses

Answer 22

helminthic parasites

Question 23

Th17 cell cytokines

Answer 23

IL-17, 22

Question 24

Th17 immune reactions

Answer 24

neutrophilic, monocytic, and inflammation

Question 25

Th 17 host defenses

Answer 25

extracellular bacteria and fungi

Question 26

early source of IL-4 in the Th2 cell pathway

Answer 26

basophils

Question 27

IL-4 roles in immune response for Th2

Answer 27

promotes B cell proliferation, IgE class switching, recruits eosinophils, blocks Th1 cell differentiation

Question 28

IL-5 roles in immune response for Th2

Answer 28

elicits B cell growth, activates eosinophils and enhances IgE production

Question 29

cytokines needed for Th17 growth

Answer 29

IL-6 and TGF-beta

Question 30

Two ways CD4 cells help activate CD8 cells?

Answer 30

1. can make cytokines that stimulate CD8 differentiation

2. can enhance the ability of APCs to stimulate CD8 differentiation

Question 31

Do CD8 cells use the B7/CD28 signal?

Answer 31

yes, they also must experience the two signal step to be activated

Question 32

CD8 cell or cytotoxic cell mechanism to apoptosis

Answer 32

antigen binding recognizes a target cell and binds to it…once bound granule exocytosis from CD8 cell…the perforin then helps granzyme enter into the target cell and granzyme induces apoptosis

Question 33

high T cell levels autoimmune disease?

Answer 33

systemic lupus

Question 34

low T cell level disease?

Answer 34

HIV/AIDS

Question 35

T cell activation by bacterial shock…what happens?

Answer 35

massive T cell response…toxic shock syndrome, food poisoning etc.

Question 36

cytokines needed for Th1 cell differentiation?

Answer 36

IL-12 and IFN-gamma