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Immunology > Lecture 12 (Exam 2) > Flashcards

Lecture 12 (Exam 2) Flashcards

1
Q

Although T cell numbers remain more or less constant over the human lifespan, pronounced _____-associated changes occur in T cell composition (naive vs. memory T cell subsets).

A

Age

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2
Q

It is well accepted that the functional naive T cell output decreases after puberty due to _______ _______, resulting in increased homeostatic proliferation of existing naive T cells and eventually phenotypic conversion of naive T cells into virtual memory cells.

A

Thymic involution

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3
Q

In contrast to the shrinking naive compartment and its impaired ability to activate and differentiate with age, the proportion of memory T cells increases during early life, remains stable throughout adulthood, but starts to show ________ changes after about 65 years.

A

Senescent

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4
Q

One of the most prominent T cell changes to occur with age is the loss of _____ expression and the progressive accumulation of highly differentiated ________ cells, mainly in the CD8+ T cell population.

A

CD28

CD28- T(EM)

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5
Q

In immunosenescence of T cells, the cells are characterized by what?

A

1) Decreases proliferative capacity
2) Shortened telomeres
3) Reduced TCR repertoire
4) Enhanced cytotoxic activity

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6
Q

Ag-activated T cells respond by producing ______ and expressing ______ receptors leading to cell proliferation. The result is expansion of the clone of T cells that are specific for the Ag.

A

IL-2

IL-2R

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7
Q

Some of the progeny differentiate into (EFFECTOR/MEMORY) cells, which serve various functions in cell-mediated immunity, and (EFFECTOR/MEMORY) cells, which survive for long periods.

A

Effector

Memory

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8
Q

Activated T cells does not produce cytokines randomly. Each subset of T helper cells tends to produce a set of particular cytokines which determine the phenotype. This process is called _________ or ________ of T helper cells.

A

Differentiation

Commitment

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9
Q

The outcome of Th0 cell activation is generation of various T helper subsets —

    • _____ cells activate a cell-mediated immune response
    • _____ cells activate an Ab-mediated immune response
    • _____ cells involved in inflammation and anti-bacterial response
    • _____ cells - follicular helper T cells remain in the LN and help B cells
A

Th1
Th2
Th17
Tfh

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10
Q

Th1, Th2, Th17, and Tfh cells are all ______ T helper cells.

A

CD4+

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11
Q

IL-23 is a pro-inflammatory cytokine composed of _____ and _____ subunits. The _____ subunit is shared with IL-12. However, IL-23 and IL-12 have different receptors and different effects.

A

p19
p40
p40

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12
Q

IL-12 produced by DCs and macrophages activate the transcription factors _____ and _____, and IFN-y produced by NK cells activates ______, which together stimulate the differentiation of naive CD4+ T cells into the _____ subset.

A

STAT4
T-bet
STAT1
Th1

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13
Q

Th1 cells amplifies their response by producing _____, which inhibits the development of Th2 and Th17 cells.

A

IFN-y

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14
Q

Th1 cells amplifies their response by producing _____, which inhibits the development of Th2 and Th17 cells.

A

IFN-y

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15
Q

Th1 cells amplifies their response by producing _____, which inhibits the development of Th2 and Th17 cells.

A

IFN-y

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16
Q

IL-4 produced by activated mast cells and eosinophils activates the transcription factors ______ and ______, which stimulate the differentiation of naive CD4+ T cells to the ______ subset.

A

GATA-3
STAT6
Th2

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17
Q

______ produced by the Th2 cells amplifies this response and inhibits the development of Th1 and Th17 cells.

A

IL-4

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18
Q

IL-1, IL-6, and TGF-B activate the transcription factors ______ and ______, which stimulates the differentiation of ______ subset.

A

RORyt
STAT3
Th17

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19
Q

______ induced by RORyt and STAT3 amplifies generation of Th17 cells in an autocrine regulatory manner.

A

IL-21

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20
Q

TGF-B may promote Th17 responses by suppressing _____ and _____ cells, both of which inhibit Th17 differentiation.

A

Th1

Th2

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21
Q

______ is a very important cytokine in activation of Th17 cells.

A

IL-23

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22
Q

______ produced by Th17 cells protect from extracellular pathogens and is involved in tissue inflammation and autoimmunity.

A

IL-17

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23
Q

This is a process that eliminates T cells which would be non-functional due to an inability to bind MHC.

A

Death by neglect

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24
Q

______ induces inflammation. Inflammation occurs at a high ratio of _____/_____.

A

IL-17

IL-17/IL-22

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25
Q

______ controls homeostasis. Constitutive low ratio of ______/______.

A

IL-22

IL-17/IL-22

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26
Q

______ stimulates T cell proliferation because its receptor shares the common gamma-chain with IL-2.

A

IL-15

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27
Q

Nontraditional _____ T cells have been termed non-conventional innate-like T cells owing to several distinguishing features that are shared with innate immune cells.

A

y/d (gamma/delta)

28
Q

Another important feature of y/d T cells is their ______ for epithelial surfaces, such as those of the liver and skin, and mucosae from respiratory, digestive and reproductive organs.

A

Tropism

29
Q

Nontraditional y/d T cells recognize conserved non-peptide antigens that are unregulated by stressed cells which resemble _______ or _______ recognized by PRRs.

A

PAMPs

DAMPs

30
Q

Upon activation, y/d T cells rapidly produce ________ that regulate pathogen clearance, inflammation, and tissue homeostasis in response to tissue stress. These cells acquire a pre-activated phenotype associated with the up regulation of memory markers early in their development. This pre-activated status allows rapid induction of effector functions following the detection of tissue stress.

A

Cytokines

31
Q

The physiological roles fulfilled by y/d T cells are varied and include:

– Protective immunity against extracellular and intracellular ________

– _______ surveillance

– Modulation of innate and adaptive immune responses

– Tissue healing and epithelial cell maintenance

– Regulation of physiological _______ function

A

Pathogens
Tumor
Organ

32
Q

Similar to BCRs and aB TCRs, y/d TCRs are generated through somatic rearrangement of _______, _______, and ______ gene segments.

A

V (variable)
D (diversity)
J (joining)

33
Q

The detection of stress-induced molecules by y/d T cells is achieved via using both TCR and non-TCR molecules (such as ______ and ______) that act separately, synergistically, or additively to activate particular y/d T cell effector functions.

A

TLRs (Toll-like receptors)

NKRs (Natural killer receptors)

34
Q

Non-traditional y/d T cells can recognize three sets of stress-induced stimuli. The first is –

– MHC-related and -unrelated TCR ligands (such as the weakly polymorphic MHC class I-like human ______ molecules, microbial and endogenous phospho-antigens).

A

CD1c

35
Q

Non-traditional y/d T cells can recognize three sets of stress-induced stimuli. The second is –

– Various cells surface molecules such as MHC class I polypeptide-related sequence A (MICA) that engage the activating ______ such as NK group 2, member D (NKG2D).

A

NKRs

36
Q

Non-traditional y/d T cells can recognize three sets of stress-induced stimuli. The third is –

– ______ and/or ______ recognized by pattern recognition receptors (PRRs) such as TLRs and dectin 1.

A

DAMPs

PAMPs

37
Q

This is a recently discovered PRR that plays an important role in anti fungal innate immunity. It is a specific receptor for Beta-glucans. Beta-glucans are glucose polymers found in the cell walls of fungi, such as zymosan.

A

Dectin-1

38
Q

Non-traditional y/d T cells have y/d TCRs and identical (with aB T cells) ______.

A

CD3

39
Q

Most y/d T cells do not express ______ or ______ co-receptors.

A

CD4

CD8

40
Q

Non-traditional y/d T cells are present where?

A

Intestine
Uterus
Tongue

41
Q

The y/d T cells develop largely in the _______, generating their defining receptor via RAG-mediated V(D)J recombination.

A

Thymus

42
Q

Functions of y/d T cells:

    • First line of _______
    • __________ (function as regulatory cells)
    • Bridging between _______ and _______ responses
A

Defense
Immunoregulation
Innate
Adaptive

43
Q

The y/d T cells may be considered a component of (INNATE/ADAPTIVE) immunity due to rearrangement of TCR genes that occurs to produce junctional diversity. However, the repertoire y/d TCRs is much less diverse than aB TCRs.

A

Adaptive

44
Q

The y/d T cells may be considered part of the (INNATE/ADAPTIVE) immunity because a restricted TCR may be used as a patter recognition receptor (PRR). The y/d TCRs recognize unpresented Ags. Several y/d T cell subsets have a memory phenotype as a consequence of peripheral stimulation by environmental or stress-induced ligands.

A

Innate

45
Q

It has been postulated that _____ T cells kill cells that become stressed as the result of a microbial infection.

A

y/d

46
Q

______ cells are T lineage cells that share morphological and functional characteristics with both T cells and NK cells.

A

NKT (Natural killer T cells)

47
Q

(HIGH/LOW) numbers of NKT cells are found virtually everywhere – T and NK cells are found in peripheral blood, spleen, liver, thymus, bone marrow, and lymph nodes.

A

Low

48
Q

In the liver, 30-50 percent of hepatic T cells are ______ cells.

A

NKT

49
Q

Following their activation, NKT cells can immediately commence ________ secretion without first having to differentiate into effector cells.

A

Cytokine

50
Q

The rapidity of their response makes NKT cells important players in the very first line of (INNATE/ADAPTIVE) defense against some types of bacterial and viral infections.

A

Innate

51
Q

In addition, many of the cytokines are secreted by NKT cells have powerful effects on a/B T cell differentiation and functions, linking NKT cells to (INNATE/ADAPTIVE) defense.

A

Adaptive

52
Q

NKT cells represent a heterogenous group of ______/______ T cells.

A

CD3+/CD56+

53
Q

NKT cells constitute only 0.2 percent of all peripheral _______ T cells. They express T cell markers such as TCR, CD40L, CD3, CD4, as well as some NK cell markers such as (CD56+).

A

Blood

54
Q

NKT cells express the Ag-specific TCR that is generated after VDJ recombination, but like innate immune cells, they do not develop immunological ________.

A

Memory

55
Q

NKT cells carry what is sometimes referred to as a “______-______” aB TCR because they express an invariant T cell receptor alpha chain.

A

Semi-invariant

56
Q

NKT cells recognize self- and foreign ______ and ______.

A

Lipids

Glycolipids

57
Q

In NKT cells, lipids and glycolipids should be presented within non-polymorphic ______ molecule – Ag presenting complex like MHC.

A

CD1d

58
Q

Upon activation, NKT cells produce a diverse array of cytokines including…

A 
IL-10
TGF-B
Th1/Th2 cytokines 
IFN-y
IL-4
GM-CSF
59
Q

Dysfunction or deficiency of NKT lead to…

A

Autoimmunity (diabetes or atherosclerosis)
Cancers
Asthma progression

60
Q

NKT cells recognition of glycolipid Ags presented by CD1d leads to a release of cytokines and expression of ______ that results in the activation of APCs and many other bystander cells.

A

CD40L

61
Q

In NKT cells, the diversity and extent of cytokine production can have a broad range of effects, ranging form enhanced cell-mediated immunity (_____ responses) to suppressed cell-mediated immunity and enhanced Ab-mediated immunity (_____ responses).

A

Th1

Th2

62
Q

NKT cells can function within the ______ ______ via direct or indirect interactions with tumor cells.

A

Tumor microenvironment (TME)

63
Q

In the (DIRECT/INDIRECT) activation pathway, NKT cells recognize lipid-CD1d complexes on surface of tumor cells and then directly mediate killing of tumor cells. By making inflammatory cytokines like IFN-y, this also helps TME-resident NK cells perform their anti-tumor cell effector functions.

A

Direct

64
Q

In the (DIRECT/INDIRECT) activation pathway, NKT cells recognize lipid-CD1d complexes on the surface of TME-resident APCs or tissue-associated macrophages (TAMs). This interaction leads to NKT cell-mediated killing of immunosuppressive TAMs, leading to a less immunosuppressive environment where tumor-infiltrating NK cells can better perform their functions.

A

Indirect

65
Q

Alternately, if the CD1d is on the surface of a TME-resident APC, the NKT cell an activate that APC and stimulate production of ______, helping resident effector cells like NK cells overcome the immunosuppressive state of the tumor.

A

IL-12

Immunology (10 decks)

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