Exam II - T Cells

Question 1

Of the profesional APCs, the most potent activators of T_H cells is:

Answer 1

mature dendritic cells

Question 2

Helper T cells respond only to:

Answer 2

processed antigen

Question 3

Antigenic classification based on the different specific sugars of bacterial lipopolysaccharides:

Answer 3

O antigen

Question 4

Also known as naive T cell:

Answer 4

Pre-T cell

Question 5

This organ contains aggregates of lymphocytes in the form of lymphoid follicles

Answer 5

Spleen

Question 6

This mitogen nonspecifically stimulates T cell mitosis:

Answer 6

Concanavalin A

(p 105)

Question 7

Somatic mutations in these immunoglobulin genes result in the secretion of antibody with increased affinity for its antigen, ie, affinity maturation:

Answer 7

variable gene regions

Question 8

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.

Answer 8

N-region nucleotides

Question 9

Lysosomal protein that sequesters free iron in phagocytes, an event that impedes bacterial replication in the phagocyte

Answer 9

lactoferrin

Question 10

Activates the extrinsic cellular apoptotic pathway:

Answer 10

Fas ligand (FasL)

Question 11

Specialized cell that delivers luminal antigen to Peyer’s Patches:

Answer 11

M (microfold) cell

Question 12

Causes lysis of antigen-bearing target cells:

Answer 12

Cytotoxic T cell (T_C; CD8⁺)

Question 13

Helps B cells produce antibodies to protein antigens:

Answer 13

Helper T cell (T_H; CD4⁺)

Question 14

functions to recognize the α domain of class I MHC molecules to enable cytotoxic T cells to bind to target cells:

Answer 14

CD8 (TCR coreceptor)

Question 15

binds to the β2 domain of the class II MHC molecule on the surface of professional APCs:

Answer 15

CD4 (TCR coreceptor)

Question 16

Also known as LFA-1:

Answer 16

CD11aCD18

Question 17

Binds T cells to CD54 molecules (ICAM-1) on APCs and target cells:

Answer 17

CD11aCD18 (also known as LFA-1)

Question 18

Constitutively-expressed membrane receptor for co-stimulatory signals (signal 2):

Answer 18

CD28

Question 19

Recombination-activating genes 1 and 2 (RAG1 and RAG2) are only found where?

Answer 19

T and B lymphocytes

Question 20

RAG1 and RAG2 are only active only in:

Answer 20

RAG1 and RAG2 are only active only in developing lymphocytes

Question 21

Which is rearranged first: α chain genes or β chain genes?

Answer 21

β chain genes rearrange first

Question 22

Which genes occur at the α locus?

Answer 22

• variable region genes (V_n)
• joining region genes (J_n)

“α-male gets all the VeeJay”

Question 23

Which genes occur at the β locus?

Answer 23

• variable region genes (V_n)
• diversity region genes (D_n)
• joining region genes (J_n)

Question 24

N-region nucleotide addition involves which enzyme?

Answer 24

terminal deoxynucleotidyl transferase (TdT)

Question 25

major co-stimulator for T_H2 cells

Answer 25

**Interleukin-1** (T_H1 cells lack IL-1 receptors and do not repond to IL-1)

Question 26

T Cell receptor for B7 proteins:

Answer 26

CD28

Question 27

*These cells* are able to respond to peptide-MHC complexes displayed on APCs that lack the co-stimulatory B7 molecule:

Answer 27

**Effector T_H Cells**

Question 28

Binds to CD40 on macrophages and B cells and activates them:

Answer 28

CD40L

Question 29

What are the 3 types of effector T cells?

Answer 29

CD4⁺ T_H1 and T_H2 cells, and CD8⁺ T cell

Question 30

Name a T Cell receptor for co-stimulation constitutively expressed on T cells. What is its ligand?

Answer 30

CD28; B7

Question 31

Which cytokines lead to differentiation into T_H1 and T_H2?

Answer 31

IL-12 (T_H1 via T-Bet) and IL-4 for T_H2 (GATA-3)

Question 32

What are the major cytokines produced by T_H1?

Answer 32

IL-2, IL-12, IFN-gamma

Question 33

What are the major cytokines produced by T_H2?

Answer 33

IL-4, IL-5, IL-10

Question 34

Produced in response to helminth parasites and other pathogens; causes proliferating CD4⁺ cells to differentiate into T_H2 cells:

Answer 34

Interleukin-4

Question 35

What are the 2 criteria for T cell selection?

Answer 35

Self MHC restrcition & self tolerance

Question 36

Do all T cells need co-stimulatory signal?

Answer 36

No, just naive T cells. Effector and memory cells do not require co-stimulatory signal

Question 37

Why are mature dendritic cells the most potent activators of naive T_H cells?

Answer 37

they constitutively express MHC molecules and co-stimulators

Question 38

Which hypervariable region displays the most diversity?

Answer 38

CDR3

Question 39

LFA-1 binds T cells to ____________ on APCs and target cells

Answer 39

LFA-1 binds T cells to **_CD54 molecules (ICAM-1)_** on APCs and target cells

Question 40

Where are T cells produced?

Answer 40

thymus