I4: TC

Question 1

Which of the following is a characteristic of innate immunity compared with adaptive immunity - A slow primary response B high antigen specificity C no immunological memory D stronger with repeated exposure

Answer 1

C no immunological memory

Question 2

All lymphocytes that leave primary lymphoid organs and have never encountered antigen are called ______ lymphocytes

Answer 2

Naive

Question 3

Which cells are professional antigen presenting cells - A neutrophils B macrophages C dendritic cells D B cells E T cells

Answer 3

B C D

Question 4

Describe the journey of a naive T cell if it does not encounter its antigen

Answer 4

Naive T cells circulate through lymph nodes spleen and other secondary lymphoid tissues then return to the bloodstream to continue immune surveillance

Question 5

Which cell is strictly required to activate naive CD4 and CD8 T cells - A neutrophil B B cell C macrophage D dendritic cell

Answer 5

D dendritic cell

Question 6

Dendritic cells found in the skin are called ______ cells

Answer 6

Langerhans

Question 7

Which properties make dendritic cells effective APCs - A high HLA class II expression B strong costimulatory molecules C long antigen presentation D antibody secretion

Answer 7

A B C

Question 8

How do T cells enter lymph nodes from blood

Answer 8

T cells pass through high endothelial venules into the paracortex of lymph nodes

Question 9

What happens after a T cell is activated in a lymph node - A immediate bloodstream exit B proliferation and temporary retention C becomes dendritic cell D apoptosis

Answer 9

B proliferation and temporary retention

Question 10

The T cell receptor consists of two chains called ______ and ______

Answer 10

Alpha and Beta

Question 11

Approximately how many identical antigen receptors exist on one T cell - A 100 B 5200 C 30000 D 52000000

Answer 11

C 30000

Question 12

Why are thousands of identical TCRs present on a single T cell

Answer 12

A high receptor density increases the chance of binding to the correct antigen on an antigen presenting cell

Question 13

TCR diversity is generated by which mechanism - A clonal selection B somatic recombination C antigenic drift D endocrine signaling

Answer 13

B somatic recombination

Question 14

V D J recombination during TCR development requires activation of ______ genes

Answer 14

RAG

Question 15

The immune system can generate approximately ______ different TCR antigen specificities

Answer 15

52000000

Question 16

Which thymocyte stages remain uncommitted and can still differentiate into other immune cells - A DN1 B DN2 C DN3 D DP

Answer 16

A B

Question 17

At which thymocyte stage does commitment to the alpha beta T cell lineage occur - A DN1 B DN2 C DN3 D DP

Answer 17

C DN3

Question 18

Define positive selection in T cell development

Answer 18

Positive selection ensures thymocytes recognize self MHC molecules and cells that cannot bind MHC die by neglect

Question 19

Where does negative selection mainly occur - A bone marrow B thymic cortex C thymic medulla D spleen

Answer 19

C thymic medulla

Question 20

Negative selection establishes self tolerance also called ______ ______

Answer 20

Central tolerance

Question 21

What happens to thymocytes that bind strongly to self antigen during negative selection

Answer 21

They undergo apoptosis preventing autoreactive cells from entering circulation

Question 22

Which molecule is associated with helper T cells according to the rule of 8 - A CD3 B CD4 C CD8 D CD28

Answer 22

B CD4

Question 23

MHC restriction means a TCR recognizes antigen only if it is - A presented by MHC B a peptide fragment C whole folded protein D from neutrophils

Answer 23

A B

Question 24

Signal 1 for naive T cell activation is interaction between TCR and the ______ ______ complex on an APC

Answer 24

Peptide HLA class II

Question 25

Signal 2 for naive T cell activation involves binding between - A TCR and HLA B CD4 and HLA C CD80 or CD86 with CD28 D IFN gamma release

Answer 25

C CD80 or CD86 with CD28

Question 26

What occurs if signal 1 occurs without signal 2 during T cell activation

Answer 26

The T cell becomes anergic and does not respond to the antigen

Question 27

Which transcription factor activates IL 2 gene expression after T cell activation

Answer 27

NFAT

Question 28

IL 2 functions as what type of growth factor - A endocrine B paracrine C autocrine D exocrine

Answer 28

C autocrine

Question 29

Differentiate paracrine and endocrine cytokine action

Answer 29

Paracrine cytokines act on nearby cells whereas endocrine cytokines travel through the bloodstream to act on distant cells

Question 30

Which cytokine promotes differentiation of Th0 cells into Th1 cells - A IL4 B IL6 C IL12 D TGF beta

Answer 30

C IL12

Question 31

Which are functions of Th1 cells - A macrophage activation B IgE production C increased HLA II expression D support CD8 cells

Answer 31

A C D

Question 32

How do Th1 cells help eliminate Mycobacterium tuberculosis

Answer 32

They produce IFN gamma which activates macrophages increasing nitric oxide and reactive oxygen production to kill intracellular bacteria

Question 33

Th2 cells are induced by ______ and mainly defend against ______ organisms

Answer 33

IL4 extracellular

Question 34

Which Th2 cytokine promotes eosinophil activation - A IL4 B IL5 C IL10 D IL13

Answer 34

B IL5

Question 35

Which diseases are associated with excessive Th2 responses - A tuberculosis B asthma C allergy D anaphylaxis

Answer 35

B C D

Question 36

Th17 cells primarily recruit which immune cells

Answer 36

Neutrophils

Question 37

Which CD4 subset suppresses immune responses using IL10 and TGF beta - A Th1 B Th2 C Th17 D Treg

Answer 37

D Treg

Question 38

Describe cross regulation between Th1 and Th2 responses

Answer 38

Th1 cytokine IFN gamma inhibits Th2 development while IL10 from Th2 or Treg suppresses Th1 responses

Question 39

CD8 cytotoxic T cells recognize antigen presented on which molecules - A HLA I B HLA II C CD28 D TCR

Answer 39

A HLA class I

Question 40

CD8 T cell antigens are processed through the ______ pathway

Answer 40

Endogenous

Question 41

Which molecules are released by cytotoxic T cells to kill targets - A perforin B antibodies C granzymes D histamine

Answer 41

A C

Question 42

Contrast perforins and granzymes in target cell killing

Answer 42

Perforins create pores in the target cell membrane and granzymes enter through the pores to trigger apoptosis

Question 43

Superantigens cause what major immune effect - A specific activation B polyclonal T cell activation C memory formation D cytokine inhibition

Answer 43

B polyclonal T cell activation

Question 44

A clinical condition caused by bacterial superantigens is ______ ______ ______

Answer 44

Toxic shock syndrome

Question 45

Which intracellular pathogens commonly trigger Th1 responses - A Mycobacterium tuberculosis B Staphylococcus aureus C Chlamydia species D Salmonella species

Answer 45

A C D

Question 46

Effector and memory T cells express ______ allowing migration to inflamed tissues

Answer 46

VLA4

Question 47

Which statement about memory T cells is correct - A require costimulation B short lived C activated by B cells or macrophages presenting antigen D only respond in lymph nodes

Answer 47

C activated by B cells or macrophages presenting antigen