immunology test 2

Question 1

where does B cell development primarily occur?

Answer 1

bone marrow

Question 2

What are the stages of a developing B cell?

Answer 2

• Early Pro-B, Pro-B, Pre-B, Immature B

Question 3

Which B cell phase undergoes Heavy Chain gene rearrangement?

Answer 3

• Pro-B

Question 4

What is the first checkpoint a developing Pro-B cell must pass in order to become a Pre-B cell? *

Answer 4

Expression of the Pre-BCR with functional heavy chain and surrogate light chain

Question 5

What proteins form the surrogate light chain?

Answer 5

• VpreB and Lambda5

Question 6

What developing B cell stage undergoes light chain gene rearrangement?

Answer 6

• Pre-B

Question 7

What is the second checkpoint a Pre-B cell must pass in order to become an Immature B cell?

Answer 7

Express a BCR with functional light chains

Question 8

What transcription factor in developing B cells allows the chromatin to open so that the Rag complex can land on the RSS promotor region and recombine genes?

Answer 8

Pax5

Question 9

How do Bone Marrow Stromal Cells assist in B cell development?

Answer 9

• SCF binds Kit on the Early Pro-B cell
• IL-7 binds IL-7R on Late Pro-B cell and the Pre-B cell

Question 10

How do Bone Marrow Stomal Cells assist in B cell Tolerance Induction?

Answer 10

• Negative Selection
• Bind auto-reactive B cell clones which can then undergo a second attempt at light chain gene rearrangement

Question 11

How do Follicular Dendritic Cells assist in B cell maturation?

Answer 11

• Attract the Immature B cell into the LN primary follicle
• Deliver final maturation signals

Question 12

How do precursor T cells enter the thymus?

Answer 12

• High Endothelial Venule

Question 13

What are the stages of T cell development? Where in the thymus would you expect each stage? *

Answer 13

CD3– (subcapsular region) | CD3++ (cortex) | CD4+/CD8+ (corticomedullary junction)

Question 14

What is the first check point in T cell development?

Answer 14

Rearrangement of beta chain genes, expression of the pre-TCR with surrogate alpha chain by a CD3– cell

Question 15

What transcription factor in developing T cells allows for gene rearrangement similar to B cells? *

Answer 15

Notch1 (also a signaling molecule)

Question 16

What T cell stage expresses the full TCR? What checkpoint had to be met? *

Answer 16

CD3++, requires successful alpha chain rearrangement

Question 17

What IL plays a role in both B and T cell development?

Answer 17

• IL-7

Question 18

What happens first, Positive or Negative selection?

Answer 18

• Positive selection in the cortex first, then negative selection in the medulla

Question 19

Negative selection protects against autoreactive T cell clones, and Positive selection determines CD4+ vs CD8+ T/F

Answer 19

T

Question 20

During positive selection, developing CD8+ T cells bind ___ and developing CD4+ T cells bind ___

Answer 20

• MHC I, MHC II

Question 21

What do these letters stand for? VDJC

Answer 21

• Variable, Diversity, Joining, Constant
• Gene regions

Question 22

Which regions are involved in heavy and beta chain gene rearrangements?

Answer 22

VDJC

Question 23

Which regions are involved in light and alpha chain gene rearrangements? *

Answer 23

VJC (no D)

Question 24

What is the process of heavy/beta chain somatic recombination?

Answer 24

• D + J = DJ
• V + DJ = VDJ
• VDJ + C = VDJC

Question 25

What is the process of light/alpha chain somatic recombination?

Answer 25

* V + J = VJ * VJ + C = VJC

Question 26

B cell activation involves which Th subtype?

Answer 26

* T follicular helper cells

Question 27

B cell activation involves crosslinking of BCRs which are clustered together in order to better recognize Ag in which form?

Answer 27

* Native

Question 28

What two proteins associated with the BCR facilitate signal transduction? *

Answer 28

Ig-alpha, Ig-beta

Question 29

When cross-linked, receptor tyrosine kinases Blk, Fyn, and Lyn phosphorylate ITAMS on Ig-alpha/ beta allowing for Syk to bind promote B cell activation. True/False?

Answer 29

True

Question 30

B cell costimulation involves CD28 binding B7. True/False

Answer 30

* False, B cell costimulation involves CD40 binding with CD40L expressed on Tfh cells.

Question 31

What cytokines induce Bcl6 expression (Tx factor) in a T cell promoting the differentiation into a T follicular helper cell?

Answer 31

* IL-6, IL-21

Question 32

What cytokines to Tfh cells secrete?

Answer 32

* IL-6, IL-10, IL-21

Question 33

Which APC is most likely to present Ag to a Naive T cell in the LN parafollicular cortex? *

Answer 33

DC (not Macrophages or B cells)

Question 34

A DC expresses costimuatory ligands inducibly or constitutively?

Answer 34

* constitutively

Question 35

When interacting with DCs in the LN parafollicular cortex, which adhesion molecules undergo a conformational change from low -> high affinity when bound, prolonging cell-cell contact and immune synapse formation?

Answer 35

* LFA-1 on the naive T cell binds to ICAM-1 on the APC What is the main function of p-SMAC? What is the function of c-SMAC? * p-SMAC:adhesion | c-SMAC:antigen binding

Question 36

What two signals are needed for activation of naive T cells?

Answer 36

* Antigen signal TCR+CD4 binding MHC II, Survival and Expansion signal CD28 binding B7(CD80)

Question 37

CD4+ and CD8+ T cells express CD4/CD8 TCR co-receptors, and when bound to MHC enhance ITAM phosphorylation via Lck allowing ZAP70 to bind- True/False?

Answer 37

True

Question 38

What are three Tx factors that activate the IL-2 promoter?

Answer 38

* NFkB, NFAT, AP-1

Question 39

Which of the IL-2R 3 chains are expressed when bound by IL-2?

Answer 39

* the alpha chain

Question 40

Where are three points of control over T cell activation and proliferation?

Answer 40

* APC needs to bind T cell, APC needs to express B7, IL2-R alpha chain must be expressed * APCs involve activation, then IL-2 promotes proliferation

Question 41

Which main cell types are involved in a CMI response? What is this response effective against?

Answer 41

CD4+ CD8+ Th1 Macrophages NK. Intracellular pathogens, anti-tumor immunosurveillance

Question 42

CD8+ cells must become sensitized by interacting with MHC I with costimulation of CD28 binding B7 and IL-2 release from CD4+ cells. T/F?

Answer 42

* True

Question 43

Once sensitized, CTLs are Ag specific for Ag presented on MHC I and can participate in direct cell killing but still require costimulation. T/F?

Answer 43

* False, once activated, CTLs do not require co-stimulation to kill.

Question 44

Which Ig isotype is expressed by plasma cells after B cells are receive signals from IL-4? Which HS reaction does this occur in?

Answer 44

* IgE. HS I

Question 45

Which HS reaction is associated with T cells?

Answer 45

* HS IV

Question 46

What form of antigen do IgG Abs seek in a HS II reaction? HS III?

Answer 46

* Surface bound antigen. Soluble floating antigen.

Question 47

A HS IV reaction involves activation of Th1 cells via antigen (hapten) presentation and the presence of which two cytokines which enhance inflammation and signal the expression of the transcription factor T-bet?

Answer 47

* IFN-gamma, IL-12

Question 48

What cytokines are produced by Th1 cells that promote a robust CMI response?

Answer 48

IL-2 (CD8->CTL), IFN-gamma (Macrophage, NK), TNF (Inflammation process)

Question 49

What cytokines induce Th1 differentiation?

Answer 49

* IL-12, IFN-gamma

Question 50

What induces Th2 differentiation?

Answer 50

* IL-4, induces GATA3 Tx factor promoting differentiation

Question 51

Th2 cells are involved in type I HS reactions against helminths and haptens (allergens) by releasing what two cytokines activating what two cell types?

Answer 51

* IL-4 (Mast cells), IL-5 (Eosinophils)

Question 52

What ILs are released by mast cells?

Answer 52

* IL-3, 4, 5, 13

Question 53

What vasoactive mediators are released by mast cells in a HS I reaction?

Answer 53

* Histamine, TNF, Prostaglandins, Leukotrienes

Question 54

The expression of what transcription factor allows thymic epithelium to educate developing T cells in the thymus? When this transcription factor is not present, what condition develops? *

Answer 54

Tx factor: AIRE | no AIRE: APCED

Question 55

What transcription factor promotes differentiation into a Treg cell? What condition develops in its absence?

Answer 55

* FoxP3 | noFoxP3:IPEX

Question 56

What cytokine promotes the expression of FoxP3 in the periphery?

Answer 56

* TGF-Beta

Question 57

Treg cells have what protein that binds to B7 prevents further expression of IL-2 and T cell proliferation?

Answer 57

* CTLA-4

Question 58

What inhibitory cytokine does a Treg secrete?

Answer 58

* IL-10

Question 59

What is immunosurveillance?

Answer 59

* Process of identifying and removing altered-self cells.

Question 60

Which phase of immunosurveillance is associated with tumor immunoediting?

Answer 60

* Equilibrium phase

Question 61

The humoral immune response alone is sufficient for tumor cell removal. True/False *

Answer 61

False, TH1 derived CMI is necessary for effective tumor cell removal. CTL (IL-12) and Macrophage (IFN-y) activation, cytotoxic TNF secretion, NK activation (IL-12)

Question 62

What kind of tumor antigen is derived from a unique protein mutation that's acquired during oncogenesis?

Answer 62

* Tumor specific antigen

Question 63

Tumor associated antigens can be derived from abnormal(fetal) or excessive protein production. True/False

Answer 63

True

Question 64

What are three ways tumor cells evade immune responses?

Answer 64

* Downregulation of surface molecules, reducing immunogenicity (MHC, B7, Antigenic modulation) * Induction of peripheral tolerance (Anergy induction, TGF-Beta & IL-10, Treg recruitment) * Creation of physical barrier

Question 65

How does monoclonal Ab cancer therapy work?

Answer 65

* TSA specific Ab be conjugated to cytotoxic drugs * Abs enhance NK killing via ADCC, can act as opsinins and aid in phagocytosis