T cell development and effector cell function (Michels)

Question 1

What type of recombination do TCR receptors undergo

Answer 1

VDJ

Question 2

How many CDR regions are there on TCR

Answer 2

3 per V region, 2 V regions

Question 3

Which CDR of TCR is the most hypervariabl

Answer 3

CDR3

Question 4

What are the differences between TCR and BCR

Answer 4

TCR have no class switching or affinity maturation. also small population of lambda and gamma T cells instead of alpha and beta

Question 5

What is the minimun number of residues that TCR recognize on MHC complex

Answer 5

1-3

Question 6

Which interation is weaker:

Ab-Ag

or

TCR binding to peptide presented on MHC

Answer 6

TCR-MHC molecule is weaker

additional surface molecules are necessary

Question 7

Describe the MHC Restriction

Answer 7

TCR must recognize MHC molecule and the presented antigen

Question 8

Where is the TCR beta chain locus and components

Answer 8

chromosome 7

leader sequences infront of variable regions then has diveristy junctional and constant regions

Question 9

describe location and components of TCR alpha chain locus

Answer 9

chromosome 14

leader, variable, juntional and constant region

Question 10

Which enzymes mediate TCR recombination

Answer 10

Rag 1 and Rag2

Question 11

What are the light chains of TCR

Answer 11

Kappa alpha and beta

Question 12

Which chains of TCR have diversity regions

Answer 12

Heavy chain and the beta chain

Question 13

During what phase of thymocyte maturation does it undergoe positive selction- describe process as well

Answer 13

Thymocytes are double positive at this stage still.

They need to bind MHC to recognize self- this is positive selection. Those that don’t bind are killed

Question 14

During what phase in thymocyte maturation do they udnergo negative selection and describe this process

Answer 14

Thymocytes are single positive at this time

Negative selection is if they bind too strongly to MHC they are killed. so those that have low affinity survive

Question 15

If you have a deficiency of MHC I or HLA I R what is the outcome on T cell populations

Answer 15

Have alot of CD4+

no CD8 CTL

Question 16

predict outcome of MHCII deficiency on T cell population

Answer 16

have lots of CD8 or CTL

no CD4+

Question 17

Cell mediated Immunity is used it what cases

Answer 17

Ingested microbes (phagosomes)

Viruses (non-phagocytotic cell)

Question 18

All nucleated cells have what type of molecule

Answer 18

MHC class I or HLA class I

Question 19

T cell expansion takes out long after antigen exposure

Answer 19

about 2 weeks

Question 20

What cytokine is responsible for clonal expansion of CD4+

Answer 20

IL2

Question 21

What is the role of effector CD4+ T cells

Answer 21

Activation of macrophages, B cells, other cells

Question 22

What is the role of effector CD8+

Answer 22

Killing infected target cells; macrophage activation

Question 23

All TCR must also have what complex

Answer 23

CD3 and epsilom

Question 24

What molecule interaction assists in slowing down lymphocytes so they can interact with MHC

Answer 24

LFA-1 on lymphocyte. ICAM-1 on T cell

Question 25

What are the T cell accessory molecules

Answer 25

CD3, epsilom, CD28, CTLA4 LFA1 VLA-4(endothelium) CD4 or 8 depending on type of T cell

Question 26

What T cell accessory molecules assist in signal transduction

Answer 26

CD28 on T cell binds to B7 on APC CD4 or 8 depending on T cell

Question 27

What is the co stimulatory molecule of T cells and its actions?

Answer 27

CD28 which binds B7of APC to produce IL2 when produced it will activate CTLA-4 which will send inhibitory signals.

Question 28

Activation of T cells triggers the expression of what proteins on T cels

Answer 28

CD40L and IL2 Receptor

Question 29

CD4+ T cells produce which cytokines

Answer 29

IL2 IL4 IL5 IFN-gamma TGF beta

Question 30

What cytokines do CD8+ T cells produce

Answer 30

IL2 IFN-gmma

Question 31

What is the role of IL2

Answer 31

proliferation and differentiation of effector and CD4+ cells

Question 32

What is the role of IL4

Answer 32

B cell switching to IgE

Question 33

What is the role of IL5

Answer 33

Activation of eosinpohils

Question 34

What is the role of IFN-gamma

Answer 34

activation of macrophages--- will produce IL12 to activate NK to release more IFN-gamma

Question 35

Role of TGF-beta

Answer 35

Inhibition of T cell activation differentiation of Tregulatory

Question 36

When and what changes in ILR to make it high affinity

Answer 36

secretion of IL2- activation of T cells induces expression of IL2R-alpha chain which makes IL2Rabgamma complex= high affinity

Question 37

Blocking CTLA-4 cases what? When would this help?

Answer 37

Keeps T cells on anti-cancer therapy but run the risk of autoimmunity

Question 38

What are the subsets of CD4+ cells and what cytokines are they assoc with

Answer 38

Th1: IFNgamma- macrophage activation Th2: IL4 IL5 IL13- humoral immunity Th17: IL17- host defense and pathogenesis of autoimmune disease T reg- suppress T cell function

Question 39

What directs the development of T cell subsets?

Answer 39

cytokines

Question 40

Describe CD4+ role in cell mediated immunity vs humoral immunity

Answer 40

cell-mediated: activates macrophages for killing phagocytosed material humoral immunity: causes secretion of Ab with enhanced abilities to neutralize and eliminate Ag

Question 41

What type of infections usually cause activation of Th1 subset

Answer 41

Intracell microbes- usually chronic because IFNgamma and TNFalpha are pretty hardcore.

Question 42

What type of infection causes activation of Th2 subset

Answer 42

helminthic parasites and allergic diseases. usually upregulate IgE and mast cell activation

Question 43

What types of infections activate the Th17 subset

Answer 43

Extracell bacteria and fungi causing neutrophilic, monocytic inflammation. Usually assoc with autoimmune and inflammatory diseases

Question 44

What activates the Th2 subset

Answer 44

TSLP thymic stromal lymphoprotein

Question 45

IFNgamma secretion activates what

Answer 45

MAcrophages B cells to stimulate C' binding Class II HLA and B7 expression on APCs

Question 46

What is the main overal role of Th17 cells

Answer 46

maintaining gut tolerance. Increased barrier function of epithelium

Question 47

What CD4 subset will be present during an asthma attack

Answer 47

Th2

Question 48

What CD4 subset will be present in multiple sclerosis patients

Answer 48

Th1

Question 49

Why is L selctin down regulated ater T cell activation

Answer 49

Don't what the T cells stuck in lymph nodes, need to return to circulation

Question 50

What T cell molecules are involved in homing native T cells and what are their complementary molecules on endothelial cells

Answer 50

L selectin- L selectin Ligand LFA-1 - ICAM-1 CCR7 - CCL19 or CCL21

Question 51

What T cell molecules are involved in himoning activated T cells and what are their complementary molecules on endothelial cells

Answer 51

E and P selctin ligands - E or P selectin LFA-1 or VLA-4 - ICAM-1 or VCAM-1 CXCR3- CXCL10

Question 52

What is the basis for delayed-type hypersensitivity reaction

Answer 52

DTH reaction: Macrophage activation by Th1 subset is depended on antigen-recognition on presenting cells (CD4) The macrophage increase MHC molecules and B7 costimulators also macrophages secrete TNF, IL1 and IL12

Question 53

What is an example of delayed-type hypersensitivity reaction

Answer 53

PPD test for TB

Question 54

What determines the outcome of intracellular infections?

Answer 54

Balance between Th1 and Th2 cell activation

Question 55

What do Th2 cells inhibit when activated

Answer 55

Microbicidal activity of macrophages

Question 56

Mycobacterium elicits what responses in patients

Answer 56

Usually Th1 and you have Tuberculoid leprosy however some patients are defective in Th1 so predominately Th2 response leading to Lepromatous leprosy

Question 57

How do CTLs induce apoptosis

Answer 57

activation of perforin and granzymes to enter cell and iduce apoptosis or Fas-FasL interactions

Question 58

How are TCRs overall different from BCRs

Answer 58

they are not secreted and do not undergo somatic hypermutation

Question 59

Which T Cells can do cell-mediated immunity

Answer 59

CD4 activate macrophages CD8 directed kill of infected cell

Question 60

Which Th subset has a response characterisitic of DTH

Answer 60

Th1 after secreting IFN-gamma classical activation of macrophages