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Immunology > Quiz 3 > Flashcards

Quiz 3 Flashcards

1
Q

Which MHC class molecule is bound by CD4+ versus CD8+ presenting cells?

A

Class II is bound by CD4+

Class I bound by CD8+

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2
Q

Which genes are expressed in MHC class II molecules versus MHC class I?

A 
DP, DQ, DR - class II
A, B, C (has beta 2 microglobulin)- Class I
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3
Q

Which cells present class II MHC genes versus class I?

A 
Profession antigen presenting cells - class II
All nucleated cells - class I
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4
Q

What cytokine up-regulates type I MHC?

A

IFN-alpha, IFN-Beta

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5
Q

What are the two types of cells called when associated with class II versus class I to their respective T-cells>?

A

Class II - antigen presenting cell (CD4 helper)

Class I - target cell (CD8+ cytotoxic)

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6
Q

What is the endogenous pathway?

A

Takes antigens from cytosol, degraded in the proteosome and trasported via TAP to become class I

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7
Q

What is the exogenous pathway?

A

Takes antigens from the extracellular milieu, MHC II associate with invariant chain, CLIP, presented on plasma membrane

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8
Q

What is the process of T cell development?

A

Hematopoiesis -> pro T cell (thymus) -> double neg (pre T)–> double positive (immature T cell) –> Single positive stage (mature Th/Tc cell) –> Naive T cell enters circulation

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9
Q

What are the two signals that t cells need for activation?

A 
TCR engagement (TCR:antigen+Self-MHC and a costimulatory signal (CD28:B7 APC)
-those only getting one signal is anergized
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10
Q

What does IL-2R bind and do?

A

IL-2R is a trimeric receptor needed for IL-2 binding and signaling at cytokine levels (T cell proliferation)
alpha - low affinity
beta/gamma -0 intermediate affinity
alpha/beta/gamma - high affinity

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11
Q

What is the difference between effector and naive t cell rolling?

A

Naive T cell rolling/diadepsis by sialy-Lewis (l-selectin), effector T cells through E/P-selectin

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12
Q

How is the t cell immune response down regulated?

A

Stop synthesis of IL-2/IL-2R and increased expression of TGF-Beta

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13
Q

What does Th1 secrete?

A

Makes IL-2, IFN-gamma, - USEFUL FOR CELL MEDIATED IMMUNITY

Induced by IL-12, IFN-gamma

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14
Q

What is Th1 particularly effective against?

A

Viruses, intracellular bacteria, malignant cells, fungi, extracellular bacteria

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15
Q

What does Th2 make?

A

IL-4, IL-5 - USEFUL FOR HUMERAL IMMUNITY

Induced by IL-4, IL-10

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16
Q

What is Th2 effective against?

A

Extracellar bacteria, helmithic parasites, extracellular viruses, allergic disease

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17
Q

What do Treg cells make?

A

TGF-beta, IL-10 for downregulation of immune response

Induced by TGF-beta, and low IL-6, IL-23

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18
Q

What does Th1 promote versus Th2?

A

Th1 - activates macrophages, NK cell, and increased cytotoxic activity
Th2 - b cell activation and antibody production, and isotype switching

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19
Q

What is the difference between memory and naive CD4 t cells?

A

CD45RO - memory

CD45A - naive

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20
Q

what are other mechanisms of CD4 t cell activation?

A 
Mitogens - non-specifically activate T cell or B cell
Superantigens - trigger TCR but are NOT processed, capable of bind directly to MHC class II to activate a significant number of T cells
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21
Q

What is the role of Th17 cells?

A

They are proinflammatory cells, induce neutrophil recruitment, produce IL-17, IL-6, induced by IL-23, IL-6, TGF-Beta, and lack of other cytokines until Th1/Th2 are upregulated

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22
Q

Which antigens stimulate B cells directly in absence of T cell help?

A

LPS, and polysaccharides with repeating identical determinants
-Produces IgM»>Ig anything else

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23
Q

Which helper cell aids in B-cell proliferation and how does it do it?

A

BCR binds antigen, Th2 cells deliver 2nd signal via CD40L and cytokines

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24
Q

What co-stimulatory signals are required for B-cell activation?

A

CD28 on T cells & B7 Complex (CD80/CD86) on Bcells

CD40L on T cells and CD40 on B cells

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25
Q

What is hyper-IgM syndrome?

A

Absence of functional CD40L

26
Q

Which cytokine is responsible for switching to IgE

A

IL-4

27
Q

Which cytokine is responsible for switching b cell to IgA

A

IL-10, TFG-beta

28
Q

What is the role of follicular dendritic cells?

A

Trap antigen and lymphocytes, antigen presented on surface of FDC to b cells

29
Q

Which cells play an important role in controlling viral infections?

A

Cytotoxic CD8+ cells that can directly kill virally infected cells and making cytokines such as IFN-gamma that inhibit vial reproduction

30
Q

What is the big difference between apoptosis and necrosis?

A

Apoptosis - suicide, cell shrinkage and plasma membrane integrity is preserved
Necrosis - murder, loss of membrane integrity and cellular swelling

31
Q

What is the Ca++ dependent mechanism of killing target cells?

A

Release of granules from CD8+ cells including perforin, and granzymes

32
Q

What is the Ca++ independent mechanism of killing target cells?

A

Expression on the surface of the CD8+ cell of cytokines (IFN-gamma, INF alpha and beta) that signal apoptosis such as FasL

33
Q

What is the CD4+ independent mechanism in which naive CD8+ cells differentiate into effector cytotoxic CD8+ cells?

A

Dendritic antigent presenting cells through MHC class I/antigen complex and costimulated through CD28 receptor

34
Q

What is the CD4+ dependent mechanism in which naive CD8+ cells differentiate into effector cytotoxic CD8+ cells?

A

CD4+ upregulate B7-1 and produce IL-2

35
Q

What are the requirements for effector CD8+ cytotoxcity?

A

Adhesion between effector and target cells (LFA-1 w ICAM-I) or CD2 w LFA3, and TCR activation by MHC class I/Ag

36
Q

What are the effector functions of NK cells?

A 
Cytotoxicity (mediated by perforin/granzymes and FasL)
Cytokine production (IFN gamma, TNF alpha, IL12)
37
Q

What do NK cells target and how do they kill their target cells?

A

Viruses, killing by release of granules that contain perforin and granzymes. Also express Fas: that will kill cells with Fas receptor

38
Q

How do NK cells recognize their targets?

A

They target cells that lack HLA class 1 expression

39
Q

How do NK cells kill cells coated with antibodies?

A

NK cells express Fc-gamma-RIII or CD16 that binds IgG1, IgG3 and kill via antibody dependent cell mediated cytotoxicity

40
Q

What are the two types of NK activator and inhibitor receptors?

A

C-type lectin family receptors (CD94, NKG2)

Killer cell immunoglobulin-like receptors (KIRs)

41
Q

How is infection blocked from being deposited and absorbed?

A

Secretory IgA, mucociliary apparatus, nonspecific mucoproteins

42
Q

How is infection propagated?

A

Virus replicates within the host cell, leading to cell death via apoptosis, infections viral particles are released for hours after cell death

43
Q

What is normal, fever, and high fever?

A

Normal - 98.6 F = 37 C
Fever - 100.5 F = 38 C
High fever - 104 F = 40 C

44
Q

What exogenous and endogenous factors are released during fever?

A

Exogenous - PAMPS, bacterial SA, LPS

Endogenous - DAMPS, IL-1TNF, IFN

45
Q

Which cytokine is responsible for inhibition?

A

IL-10, inhibits cytokine production, inhibits inhibition of apoptosis of neutrophils

46
Q

What is the immune system function?

A

Resist pathogens, microbes that cause diease, foreign bodies and abnormal cells. Resistance to pathogens is primary

47
Q

What makes a bacteria gram positive?

A

Thick peptidoglycan layer

48
Q

How does extracellular bacteria cause pathology?

A

Inflammation, or producing toxins

49
Q

How does intracellular bacteria cause pathology?

A

Causing chronic infections which activate and sustain immune response against host tissue

50
Q

What is unique about parasites?

A

Unicellular and multicellular eukaryotic organisms that account for more morbidity and mortality

51
Q

What are the exterior defenses?

A

Skin, mucosal epithelium, lysozyme in secretions, acidic environment of the stomach

52
Q

What are interior defenses?

A

Causes inflammation, neutrophils, macrophages, innate defense mechanisms are presents prior to exposure to infectious agents

53
Q

What are the receptors of innate immunity?

A

Pattern recognition molecules, toll-like receptors

54
Q

What is the general immunity for extracellular bacteria?

A

opsonizing antibody IgG enhances phagocytosis, C3b, neutralizing antibody, complement activation

55
Q

What is the general mechanism for intracellular bacteria?

A

CD4+ T cell to Th1 secreting IFN-gamma to activate macrophages, CD8+ T cell into cytotoxic T cells

56
Q

What is the evasion strategies for bacteria?

A

Exotoxins, IgA protease, capsules, prevention of phagosome0lysosome fusion, escape from the phagosome

57
Q

What is the mechanism immunity to viruses?

A

Inhibit IFN alpha and beta, NK cell lysis, neutralizing antibodies IgG, IgA, complement, cell mediated

58
Q

What are virus evasion strategies?

A

Down regulation of MHC class I proteins (attacked by NK cells), Virokines (EBV) and viroreceptors (IL-10)

59
Q

What is the mechanism for immunity to parasites?

A

Macrophages, Th1 responses are most important, activation of Th2 results in IgE, activation of eosinophils

60
Q

What is the evasion strategies of parasites?

A

Cuticle formation, antigenic variation

Immunology (4 decks)

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