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A&I > Immune Mechanisms > Flashcards

Immune Mechanisms Flashcards

1
Q

What is hapten-carrier effect?

A

Small-molecule antigen requires a larger carrier to stimulate adaptive response. This process is achieved with hapten-specific B cells and carrier-specific T cells.
- basis of conjugated vaccines

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2
Q

What are the common superantigens (4) and related diseases?

A

1,2. SEB and SEC from Staph aureus food poisoning

  1. TSST from staph aureus for toxic shock synd
  2. SPE-C from strep pyogenes for toxic shock synd
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3
Q

Which type of T cell recognizes lipid antigens and what molecule is involved? (2)

A
  • NK T cells recognize lipid antigens and CD1 molecules are involved
  • gamma delta T cells
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4
Q

what antigens are T cell dependent and which are T cell independent?

A

Dependent - protein Ag

Independent - polysaccharide, nucleic acid, lipids

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5
Q

Where do superantigens bind?

A

Vbeta region of TCRs that are outside of the peptide-binding groove on the MHC molecule

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6
Q

what is the name of molecules in vaccine that enhance the immune response?

A

Adjuvants

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7
Q

what is the difference between an antigen and immunogen?

A
  • Ag = recognized by immune system

- immunogen = stimulates an immune response

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8
Q

what do epitopes bind to?

A

Ab or T cell receptor

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9
Q

what is an acute multi-organ inflammatory syndrome that can happen in response to infections or immune therapies

A

cytokine release syndrome

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10
Q

what are the chief cytokines in cytokine release syndrome (3)

A

IL- 6, IL -10, TNF alpha

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11
Q

what is potential complication of (CAR)-T therapy

A

cytokine release syndrome

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12
Q

What vaccination have purely polysaccharide Ag (2)

A

23-valent pneumococcal vaccine, typhoid vaccine

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13
Q

what is the binding site for CD8 on the MHC class I molecule

A

alpha 3

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14
Q

what chain makes up the peptide binding cleft in MHC class I molecules

A

alpha 1 and 2

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15
Q

MHC class I molecule presents which type of Ag and where does the Ag-MHC class I loading happen?

A

presents both intracellular antigens (ex viral Ag in cytoplasm) and extracellular Ag (via cross presentation).
- the loading site is endoplasmic reticulum (ER)

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16
Q

in which chromosomal region are the TAP proteins located?

A

MHC class II locus, which is involved in peptide processing for MHC class I.

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17
Q

MHC class II molecule presents which type of Ag? where does Ag-MHC class II loading happen?

A

presents extracellular Ag (ex Ag from phagocytosed bacteria)
- loading site is phagolysosome

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18
Q

which cytokines are important for Tregs? (2)

A

IL-10 and TGF beta

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19
Q

Where does Pepsin cleave and what is the result?

A

Ig below the hinge region at multiple sites and produces a single F(ab)2

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20
Q

what is RF

A

Ab against the Fc portion of IgG

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21
Q

which Ig class has the highest plasma concentration? Highest total body concentration?

A

IgG and IgA

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22
Q

what is secretory immunity?

A

small quantities of IgG and IgM are secreted into the gut lumen and bind to microbes and toxins to neutralize them

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23
Q

which cytokines primarily activate NKFB

A

IL1, TNF and IL-17 families

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24
Q

what are Th2 cytokines? (6)

A

IL- 4, 5, 9, 13, 25, 31

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25
Q

which cytokine is involved in IgA class switch?

A

TGF beta

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26
Q

which cytokine inhibits class switching to IgE and IgG4?

A

IFN gamma

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27
Q

what is the function of IL- 6 (4)

A

pro-inflammatory cytokine, stimulates synthesis of acute-phase protein by hepatocytes, stimulates production of neutrophils, and stimulates growth of B lymphocytes

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28
Q

what molecules belong to the Ig superfamily (10)

A

TCR, MHC molecules, CD4, CD8, CD19, B7-1, B7-2, Fc receptors, KIR and VCAM-1

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29
Q

what is the role of the FcRn receptor? (4)

A

FcRn receptor binds to IgG and allows it to be endocytosed.

  • protects IgG from lysosomal degradation and recycles it to the cell surface, accounting for the long half-life of IgG in humans
  • also the mechanism by which IgG is transported across the placenta and fetal intestine.
  • IgG3 has the shortest half-life because it poorly binds to FcRn
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30
Q

mutation in SAP causes which disease?

A

X linked lymphoproliferative syndrome (XLP)

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31
Q

immunosuppressant cyclosporine binds to which molecule in T cell signaling pathway?

A

cyclosporine binds to cyclophilin, also called immunophilin. The drug-protein complex inhibits calcineurin and therefore inhibits NFAT translocation to the nucleus

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32
Q

what CD molecules are in the BCR coreceptor?

A

CD19, CD21, and CD81

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33
Q

which chemokine receptor is associated with WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome?

A

CXCR4

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34
Q

which integrin molecule is important for gut homing by binding to MAdCAM?

A

alpha4beta7

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35
Q

which receptors are associated with CCL5 (RANTES)

A

CCR 1, 3, 5

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36
Q

what is another name for CCL 17? what receptor is it associated with?

A

TARC; CCR4

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37
Q

what ligand does Rhinovirus bind to?

A

ICAM-1

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38
Q

which chemokine receptor is required for HIV entry to CD4 T cells?

A

CCR 5

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39
Q

what is the defect in LAD-2?

A

PMNs cannot express carbohydrate ligands for E and P selectins

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40
Q

upon first exposure to a medication, when might a patient develop symptoms of serum sickness?

A

7-12 days

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41
Q

which component is shared by IL-4 and IL-13 receptors?

A

IL-4alpha which is targeted by dupilumab

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42
Q

what is the result of IFN gamma receptor deficiency?

A

susceptibility to Mycobacterium tuberculosis and other intracellular bacteria

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43
Q

what interleukin is excessively produced in cryopyrinopathies?

A

IL-1 beta

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44
Q

what is the function of LRBA?

A

Recycles/maintains intracellular stores of CTLA4, which can stop T cell activation

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45
Q

which complement deficiency is X linked?

A

properdin

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46
Q

what two molecules inhibit MAC formation?

A

CD59 and S protein

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47
Q

which complement receptor is implicated in PNH (paroxysmal nocturnal hemoglobinuria)?

A

CD55 and CD59

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48
Q

what is the main source of Factor D?

A

adipose tissue

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49
Q

anti-C1q antibody is found in which disease process?

A

HUVS (hypocomplementemic urticarial vasculitis)

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50
Q

contact activation pathway is initiated by which factor?

A

Factor XII

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51
Q

bradykinin acts on what receptor on endothelial cells?

A

B2 receptor

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52
Q

what are the primary immunoglobulins involved with type II hypersensitivity

A

IgG and IgM

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53
Q

IgG and IgM activate which complement pathway?

A

classical pathway

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54
Q

what is the binding site for CD4 on the MHC class II molecule?

A

beta2

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55
Q

which chain makes up the peptide binding cleft in MHC class II molecules?`

A

alpha1 and beta1

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56
Q

where is HLA-G located?

A

fetal derived placental cells

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57
Q

what is the role of HLA-DM?

A

removes CLIP, allowing antigenic peptides to load into MHC class II binding cleft

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58
Q

mutations in which transcription factors can lead to MHC class II deficiency? (4)

A

MHC2TA, RFX5, FRXAP, FRAXANK

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59
Q

what are the possible outcomes of central T cell tolerance?

A

apoptosis (negative selection) – strong binding affinity
- Treg dev – intermediate binding affinity

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60
Q

what cells in the thymus express AIRE

A

medullary thymic epithelial cells (MTECs)

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61
Q

what are the possible outcomes of central B cell tolerance?

A

apoptosis (negative selection)
receptor editing
anergy

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62
Q

what are the mechanisms of peripheral T cell tolerance? (3)

A

apoptosis
suppression by Treg cells
anergy

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63
Q

what are the mechanisms of peripheral B cell tolerance? (2)

A

apoptosis, anergy

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64
Q

what has the greatest binding affinity for C1q? (4)

A

IgM > IgG3 > IgG1> IgG2

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65
Q

C3 nephritic factor is associated with which diseases? (2)

A

type II membranoproliferative glomerulonephritis and partial lipodystrophy

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66
Q

patients with C2 deficiency are at risk for which infections (2)

A

strep pneumo and Hib

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67
Q

what enzymes degrade bradykinin? (2)

A

ACE, DPP-4

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68
Q

how are serum sickness and arthus reaction similar and different?

A

both are type III hypersensitivity rxn, but serum sickness is systemic and arthus reaction is local

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69
Q

what receptor is involved with the inflammasome?

A

NLR family receptors

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70
Q

which TLR does not signal through MyD88

A

TLR3

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71
Q

which TLR can signal through both MyD88 dependent and independent pathways?

A

TLR4

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72
Q

which TLRs are present in the intracellular compartment?

A

TLR 3,7,8,9

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73
Q

how do PAMPs differ from DAMPs?

A

PAMPs- conserved microbial sequences

DAMPs - endogenous molecule from damaged or dying cells

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74
Q

which TLR binds lipopolysaccharide (LPS) on gram negative bacteria?

A

TLR4

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75
Q

unmethylated CpG motifs bind to which TLR?

A

TLR 9

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76
Q

what gene defects increase susceptibility to recurrent herpes encephalitis? (6)

A

TLR3, UNC93B, TRAF3, TRIF, TBK1, IRF3

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77
Q

name the cytosolic pattern recognition receptors (3)

A

NLRs, include NOD and NLRP family
RLRs, include RIG-1, MDA-5
CDS, include AIM2 and STING

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78
Q

Dectin-1 mutation leads to what disease?

A

chronic mucocutaneous candidiasis

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79
Q

name the preformed mediators stored in mast cells (6)

A

histamine, tryptase, acid hydrolases, cathepsin G, carboxypeptidase, +/- chymase

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80
Q

name the preformed mediators stored in eosinophils (5)

A

MBP, ECP, eosinophil peroxidase, lysosomal hydrolase, lysophospholipase

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81
Q

disease causing immune complexes are formed under what conditions?

A

moderate antigen excess

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82
Q

AGEP (Acute generalized exanthematous pustulosis) is what subtype of type IV hypersensitivity?

A

type IVd

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83
Q

what somatic recombination process introduces the greatest diversity in immune receptors and which enzyme is important in this process?

A

junctional diveristy; TdT enzyme is important in this process

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84
Q

C3 convertase in classical and alternative pathway

A

C4b2a for classical.
C3bBb for alternative

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85
Q

C5 convertase in classical and alternative pathway

A

C4b2a3b
C3bBb3b

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86
Q

which complements are chemoattractants? (4)

A

C2b, C3a, C4a, C5a

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87
Q

which complement is anaphylotoxin?

A

C5a

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88
Q

order of binding affinity of C1q (4)

A

IgM > IgG3 > IgG1 > IgG2
- IgG4 cannot bind C1q

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89
Q

name two things that inhibit formation of MAC

A

S protein and CD59

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90
Q

what is a superantigen?

A

antigens that activate a large number of polyclonal T cells by directly binding to Vbeta domain of TCR and the external surface of MHC II molecule (outside of peptide binding cleft)
- leads to massive cytokine release

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91
Q

name four superantigens

A
  • Staph enterotoxin B
  • staph enterotoxin C
  • toxic shock syndrome toxin (staph. aureus)
  • strep pyrogenic exotoxins
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92
Q

name three main cytokines involved in cytokine storm

A

IL6
TNF alpha
IL 10

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93
Q

Describe immune cells involved, surface molecule involved, B cell response and vaccines for protein antigen

A
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94
Q

Describe immune cells involved, B cell response and vaccines for polysaccharide antigen

A
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95
Q

Describe immune cells involved, and surface molecule involved for lipid antigen

A
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96
Q

amino acid epitopes are recognized by what type of cell?

A

T cells
- linear determinants of amino acids only
- length limited by MHC binding cleft

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97
Q

are conjugated vaccines T cell dependent or independent? (3 vaccines)

A

T cell-independent antigens linked to a carrier protein, that can trigger a T cell DEPENDENT response and memory
- 13 valent s.pneumo
- Hib
- meningococcal

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98
Q

MHC molecules are located on which chr? (2)

A

chr 6 (expressed co-dominantly)
- beta microglobulin for MHC class I is on chr 15

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99
Q

describe domains of MHC class I molecule and its location

A
  • three alpha chains and one beta microglobulin
  • located on nucleated cells
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100
Q

describe domains of MHC class II molecule and its location

A
  • two alpha chains and two beta chains
  • located on APCs, thymic epithelia, and activated T cells
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101
Q

what does MHC restriction mean

A
  • can only present peptides to T cells
  • does NOT present lipids, nucleic acids, and polysaccharides
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102
Q

which cytokines induce expression of MHC class I?

A

IFN alpha, beta and gamma

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103
Q

which cytokines induce expression of MHC class II?

A

IFN gamma

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104
Q

class III region on chr 6 also encodes for? (3)

A
  • complements - Factor B, C4 and C2
  • heat shock proteins
  • cytokines - TNF alpha and lymphotoxin alpha and beta
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105
Q

describe antigen processing and MHC class I presentation

A
  • newly made MHC class I remains in ER by interacting with chaperone proteins
  • cytoplasmic proteins are degraded by proteasome
  • antigenic peptides are transported into ER by TAP proteins (both TAP1 and 2 subunits must be present)
  • tapasin brings TAP and MHC molecule close together
  • antigenic peptides are loaded onto the new MHC I
  • transported to cell surface
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106
Q

describe antigen processing and MHC class II presentation

A
  • extracellular antigen is endocytosed –> into phagosomes
  • fuse with lysosome –> phagolysosome (protease called cathepsin degrade peptides)
  • new MHC II is transported to phagolysosome from ER
  • invariant chain that occupied the binding cleft is degraded by proteases –> leaves CLIP behind
  • HLA-DM removes CLIP and allows antigenic peptide to be loaded
  • transported to cell surface
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107
Q

what is cross presentaion?

A

the ability of APCs (mostly DC) to present extracellular antigens with MHC class I molecules to CD8 T cells
- extracellular antigens are usually presented on MHC class II

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108
Q

MHC class I deficiency (bare lymphocyte synd) (5)

A
  • mutation in gene encoding for TAP or tapasin
  • AR
  • bacterial sinopulm infections, necrotizing granulomatous skin lesions, necrobiosis lipoidica
  • CD8 lymphopenia
  • tx with abx, aggressive pulm toilet and chest PT
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109
Q

MHC class II deficiency (bare lymphocyte synd) (6)

A
  • mutation in MHC2TA, RFX5, FRXAP, FRXANK
  • AR
  • viral, bacterial, fungal and/or protozoal infections
  • infections usually start in the first year of life
  • CD4 lymphopenia, absent germinal centers, hypogamm
  • tx: HSCT, IVIG, abx
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110
Q

what happens when a developing T cell reacts to self-antigen in the thymus? (2)

A

negative selection (strong binding affinity and high concentration) –> apoptosis
intermediary binding –> Treg cell

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111
Q

what is AIRE gene?

A
  • expressed by medullary thymic epithelial cells (MTECs)
  • promote expression of non-thymic tissue antigens
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112
Q

mutation in AIRE gene leads to (3)

A

autoimmune polyglandular syndrome (aka APECED)
- lymphocytes are not deleted or tolerized to endocrine self-antigens during selection in the thymus
- therefore, endocrine organs (parathyroid, adrenal and pancreatic cells) are attacked by autoreactive T cells and autoantibodies

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113
Q

name three outcomes when B cell reacts to self antigen in the bone marrow

A
  • receptor editing
  • apoptosis (negative selection)
  • anergy
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114
Q

describe receptor editing process (4)

A
  • reactivation of RAG1/2
  • new kappa light chain is given (always first, then lambda)
  • if still unsuccessful, a lambda light chain is used
  • if still fail, apoptosis
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115
Q

T cell peripheral tolerance outcomes (3)

A

apoptosis, suppression by Tregs, anergy

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116
Q

B cell peripheral tolerance outcomes (2)

A

apoptosis or anergy
- receptor editing only in central organ.

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117
Q

surface markers for Tregs (3)

A

CD3, CD25 (IL2R alpha), FoxP3 (forkhead box P3)

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118
Q

cytokines that are essential in survival of Tregs (2)

A

IL2 and TGF beta

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119
Q

tolerance or regulation is maintained by which two cytokines?

A

IL10 (target MO and DC) and TGF beta (inhibits lymphocytes and MO)

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120
Q

Apoptosis intrinsic pathway

A

T cell stimulation without costim by self antigens –> activate Bim (pro-apoptotic member of Bcl-2 family)
- Bim binds to Bax and Bak (pro-apoptotic effector proteins)
- insert into mitochondrial membrane –> inc permeability and cell death
(also known as mitochondrial pathway)

121
Q

apoptosis extrinsic pathway

A
  • FasL (CD95L, on T cells) is upregulated on repeatedly activated T cells
  • FasL can interact with Fas on a cell with self-antigen
  • lead to either deletion of the cell or the T cell.
  • via caspase system
122
Q

Steps of peripheral B cell tolerance (3)

A

chronic antigen recognition downregulates CXCR5 –> inhibits B cell homing and interaction with T cells –> cell death

123
Q

what is a dominant negative mutation?

A

when a mutation, when expressed, leads to product that interferes with the activity of wild-type allele.

124
Q

what does histone acetylation do?

A

opens the chromatin to allow transcription

125
Q

what does DNA methylation do?

A

typically represses gene expression

126
Q

earliest B cell stage that produces Ig

A

pre-B cell stage

127
Q

what is the most variable part of an Ig

A

CDR3

128
Q

de-glycosylated IgG cannot ___ (2)

A
  • cannot bind Fcgamma Rs and C1q effectively
  • therefore, unable to trigger antibody-dependent cell-mediated cytotoxicity and complement activation
129
Q

decreased glycosylation is associated with which autoinflammatory diseases? (4)

A
  • RA, SLE, Crohn’s and TB
130
Q

what is a rheumatoid factor?

A

its is an Ab against Fc portion of IgG.
usually in the form of IgM, but can be in any form

131
Q

definition of affinity (3)

A
  • strength of binding between a single antigen epitope and Ig.
  • indicated by Kd.
  • lower Kd = higher affinity
132
Q

Ig isotype that has the highest affinity

A

IgE

133
Q

difference between somatic hypermutation and class switch recombination

A
  • somatic hypermutation –> changes in V, not C regions.
  • class switch –> changes C, not V regions. does NOT change Ag specificity
134
Q

what is junctional diversity?

A

random (nontemplated) addition/removal of nucleotide sequences at junctions between V,D, and J regions –> extensive somatic variability in immune receptors

135
Q

what are the CD markers for different FcgammaRs?

A

FcgRI - CD64
FcgRII - CD32
FcgRIII - CD16

136
Q

what is the CD marker for FceRII?

A

CD23

137
Q

isotype switching to IgA is stimulated by which cytokines (2)

A

TGFb and IL-5

138
Q

which T cells are not HLA restricted?

A

gamma delta T cells

139
Q

most important cytokine produced during T cell activation

A

IL-2 (binds to CD25/IL-2Ra to give T cell survival signal and proliferation)

140
Q

which disease cannot form immunological synapse?

A

Wiskott Aldrich syndrome, due to its defective actin cytoskeleton -> cannot polymerize T cells

141
Q

Full activation of T cells require?

A

prolonged interaction between T cells and APC via LFA1 on T cell and ICAM on APC, as part of the immune synapse

142
Q

ZAP 70 deficiency

A

SCID with no CD8+Tcells or T cell function, but with normal B and NK cells (T-B+. NK+)

143
Q

function of NFAT

A

encodes for cytokines IL-2,4, TNF
- Tacrolimus blocks T cell cytokine gene transcription

144
Q

function of NFKB

A

essential for cytokine synthesis and plays an important role in lymphocyte dev, neoplasms, and formation of secondary lymphoid organs

145
Q

what is part of a BCR complex?

A

surface Ig and Iga and Igb chains

146
Q

what is part a B cell co-receptor complex? (3)

A

Cd21 (CR2) - Cd19 - Cd81.
- C3b bound to Ag –> binds to CD21 –> brings complex near BCR –> CD19 has an ITAM that is phosphylated, which recruites Lyn to enhance phosphorylation of Iga/Igb

147
Q

inhibitory receptors on NK, T and B cells (1 each)

A
  • NK cell: KIRs
  • T cell: CD28 family (CTLA-4/CD152, PD-1)
  • B cell: FcgRIIb (also on DCs and MOs)
148
Q

which cytokine receptors contain a common gamma chain? (6)

A

IL -2,4,7,9,15,21

149
Q

which cytokine receptors share a common beta chain? (3)

A

IL-3, IL-5, GM-CSF

150
Q

what happens when TNF-RI receptor is bound?

A

apoptosis via caspase 8

151
Q

GoF mutation of NALP leads to? (3)

A

uncontrolled IL-1 production and autoinflammatory syndromes
- IL-1b is cleaved by caspase 1, which is activated by NALP.
- IL-1Ra is a competitive inhibitor of IL-1 (Anakinra)

152
Q

IRAK-4 deficiency leads to

A

susceptibility to pyogenic infections, esp Strep pneumo

153
Q

patients with IL-12Rb1 mutations are susceptible to which infections?

A

intracellular bacteria, notably Salmonella and atypical mycobacteria

154
Q

which JAK/STAT pathway is activated by IL2?

A

JAK3-STAT5

155
Q

which cytokine and transcription factor promotes differentiation of naive CD4 T cells to the Th1 subset?

A

IFN gamma - STAT1 - Tbet

156
Q

IL-4 uses which STAT?

A

STAT6

157
Q

which JAK/STAT pathway does IL-5 use?

A

JAK2-STAT3

158
Q

what is Castleman’s disease? (8)

A

hyperproduction of IL-6
- angiofollicular lymph node hyperplasia
- fever, microcytic anemia, lymphadenopathy, hypoalbuminemia, elevated CRP and normal bone marrow iron

159
Q

Hot T-Bone stEAk mnemonic

A

IL-1: fever (Hot)
IL-2: stimulates T cells
IL-3: stimulates Bone marrow
IL-4: stimulates IgE
IL-5: stimulates IgA

160
Q

chemokines or receptors associated with HIV/AIDS (5)

A

CCR5, CCL3L1, CXCR4, CCR2, CXCL12

161
Q

cell adhesion molecule pair involved in lymphocyte homing to LN

A

CCL19/21 - CCR7

162
Q

cell adhesion molecule pair involved in pro Th2 response

A

CCL17/22 - CCR4

163
Q

receptor for CCL5 (RANTES)

A

CCR 1,3,5

164
Q

receptor for CCL11 (eotaxin)

A

CCR3

165
Q

receptor for CCL17 (TARC)

A

CCR4

166
Q

receptor for CXCL8 (IL-8)

A

CXCR1,2

167
Q

CD marker, location, ligand, and function of P selectin

A
  • C62P
  • on Platelets, and Weibel-Palade bodies of endothelium
  • lingand:PGSL and sLex
  • Function: bind PMNs, T cells and monocytes
168
Q

CD marker, location, ligand, and function of E selectin

A
  • CD62E, ELAM
  • on endothelium
  • ligand: ESL-1, CD15, PGSL, sLex
  • function: homing of T cells to peripheral sites of inflammation
169
Q

CD marker, location, ligand, and function of L selectin

A
  • Cd62L, LAM-1
  • on lymphocytes and leukocytes
  • ligand: GLYCAM-1, MADCAM-1, Cd34, and sLex
  • function: homing to lymph node HEV (GLYCAM-1) and PMN rolling (MADCAM)
170
Q

TLRs that are on cell membrane (5)

A

TLR 1,2,4,5,6

171
Q

which cytokine is necessary for Th1 differentiation?

A

IL-12

172
Q

Name associated condition with CXCL4

A

Heparin-induced thrombocytopenia
-CXCL4 = platelet factor 4 (PF4)

173
Q

name associated chemokines with asthma/allergies (5)

A

CCL2,5,7,11, CXCL8

174
Q

name implicated chemokines for HIV

A
  • CCR5: homozygotes - no infection. heterozygote - slow progression of the infection
  • CXCR4: T trophic
  • CCL3L1: low level –> higher HIV acquisition, viral load, worse disease
175
Q

steps of the alternative complement pathway

A
176
Q

steps of classical complement pathway

A
177
Q

steps of MBL complement pathway

A
178
Q

which proteins inhibit MAC formation?

A

S protein and Cd59

179
Q

what is CR4 a marker of?

A

dendritic cells

180
Q

what does CR2 (CD21) do?

A
  • binds to C3d (not C3b) and provides a second signal for B cell activation by Ag
  • trap Ab-Ag complexes within germinal centers
181
Q

what does CR1 bind to and what is its function?

A
  • binds to C3b, C4b
  • dissociates C3 convertase
  • phagocytose C3b and C4b coated particles
182
Q

what does CR3 bind to and what is its function?

A
  • alternative names = Mac-1, Cd11b/CD18
  • ICAM-1
  • phagocytosis, leukocyte adhesion to endothelial cells
183
Q

what does CR4 bind to and what is its function?

A
  • alternative names = gp150/95, CD11c/CD18
  • binds to iC3b
  • phagocytosis
184
Q

what does CD46 (MCP) bind to and what is its function?

A
  • binds to C3b, C4b
  • is a cofactor with Factor I to inactivate C3b and C4b
  • associated with atypical HUS
185
Q

what does CD55 (DAF) bind to and what is its function? (3)

A
  • binds to C3b, C4b
  • prevents formation of C3 convertase
  • associated with paroxysmal nocturnal hemoglobinuria
186
Q

what does CD59 (protectin) bind to and what is its function?

A
  • binds to C7, 8
  • prevents C9 from binding to C5b-8
  • associated with paroxysmal nocturnal hemoglobinuria
187
Q

three examples of microorganisms using complement receptors for cell entry

A
  • opsonized HIV can infect cells via CR1 (associated with enhanced viral replication and sustained HIV infection)
  • EBV can bind CR2 to facilitate cell entry
  • M. TB uses CR3
188
Q

deficient complements when CH50 is absent, but AH50 is ok

A

C1q, C1r, C1s, C2, C4

189
Q

deficient complements when CH50 is ok, but AH50 is absent (3)

A

Factor B, D, properdin

190
Q

deficient complements when both CH50 and AH50 are absent

A

C3,5,6,7,8,9

191
Q

deficient complements when both CH50 and AH50 are absent and C3 is absent also.

A

Factor H, I

192
Q

pemphigus vulgaris is which type of hypersensitivity reaction and what is MOA?

A
  • type II
  • anti-desmoglein 1/3 Ab mediated destruction of keratinocyte junctions
193
Q

Goodpasture syndrome is which type of hypersensitivity reaction and what is MOA?

A

anti-basement membrane Ab mediated complement and phagocyte activation
- type II

194
Q

Myasthenia Gravis is which type of hypersensitivity reaction and what is MOA?

A

anti-acetylcholine receptor Ab that inhibits receptor function and downregulates receptor
- type II

195
Q

what is Arthus reaction

A
  • type III hypersensitivity reaction
  • production of local edema, PMN migration, hemorrhage and necrosis at the site of injection
  • due to local vasculitis caused by immune complex deposition
  • peak at 4-10h
196
Q

what kind of cells/cytokines are involved in type IVa hypersensitivity reaction? and what are the associated diseases? (3/2)

A
  • Cd4+ Th1 cells (IFNg, TNFa, IL2)
  • MO, NK cells
  • contact derm, TB
197
Q

what kind of cells/cytokines are involved in type IVb hypersensitivity reaction? and what are the associated diseases? (3/2)

A
  • CD4+ Th2 cells (IL4,5,13)
  • eos, B cells
  • DRESS, morbilliform drug rash
198
Q

what kind of cells/cytokines are involved in type IVc hypersensitivity reaction? and what are the associated diseases?

A
  • Cd8+ T cells (perforin, granzyme)
  • Cd4+ T cells
  • psoriasis, drug induced hepatitis
199
Q

what kind of cells/cytokines are involved in type IVd hypersensitivity reaction? and what are the associated diseases?

A
  • T cells , PMNs
  • contact derm, AGEP (Acute generalized exanthematous pustulosis)
200
Q

which cytokines does caspase 1 cleave to make them active? (2)

A

IL-1b and IL-18

201
Q

GoF mutation in NLRP3 leads to?

A

cryopyrin-associated periodic syndrome (CAPS)

202
Q

which signaling pathways does MyD88 activate? (3)

A
  • NFkB and AP-1
  • involved in all TLRs, EXCEPT TLR3
203
Q

what kind of signaling pathway does TLR3 activate?

A
  • uses adaptor protein TRIF/TRAF and activates IRF3,7 –> type I IFN
204
Q

which TLR can use both MyD88 and TRIF?

A

TLR 4 (on the cell membrane)

205
Q

PRRs associated with HSV1 encephalitis

A

UNC93B, TLR3

206
Q

Transcription factor defects associated with recurrent pyogenic infections like strep or staph

A

MyD88, IRAK4

207
Q

PRRs associated with canonical incisors, ectodermal dysplasia, and recurrent bacterial infections

A

NEMO or Ikk

208
Q

PRRs associated with Crohn’s or Blau’s syndrome

A

NOD2

209
Q

PRRs associated with chronic mucocutaneous candidiasis (2)

A

Dectin 1, CARD9

210
Q

PRRs associated with pulmonary immune deficiency with infectious and mycobacterial susceptibilities

A

NEMO

211
Q

pathway for PI3K (4)

A
  • PIP2 becomes PIP3 by PI3K
  • PIP3 activates PDK1
  • Akt is then activated
  • leads to cell survival
212
Q

MAP kinase pathway with Grb2-SOS (3)

A
  • Lyk - ZAP70- LAT
  • Grb2-SOS –> Ras.GTP
  • transcription of c-Fos
213
Q

MAP kinase pathway with Vav (5)

A
  • Lyk - ZAP70-LAT
  • Vav activates Rac.GTP
  • JNK activated
  • c-Jun is phosphorylated
  • later combines with c-Fos to become AP-1 transcription factor
214
Q

PLCg - IP3 pathway (7)

A
  • Lck-ZAP70-LAT
  • Itk (BTK in B cells) - PLCg
  • PIP2 hydrolyzed to IP3 by PLCg
  • IP3 - STIM senses lack of Ca in ER
  • brings extracellular Ca to the cytoplasm
  • activates Ca-calmodulin
  • calcineurin activated –> NFAT
215
Q

PLCg - DAG pathway (5)

A
  • Lck-ZAP70-LAT
  • Itk (BTK in B cells) - PLCg
  • PIP2 hydrolyzed to DAG by PLCg
  • activates protein kinase C (PKC)
  • NFkB
216
Q

Which important cytokine is involved in the proliferation and function of natural killer cells and T- regulatory lymphocytes?

A

IL-2

217
Q

homing pattern of Th1 (4)

A
  • CXCR3, CCR5 = tissues
  • E and P selectin ligands
218
Q

homing pattern of Th2 (3)

A

CCR3,4,8 = mucosa

219
Q

homing pattern of Th17 (2)

A

CCR6-CCL20 produced by tissue cells and macrophages

220
Q

IFN gamma inhibits (2)

A

Th2 and Th17 differentiation

221
Q

IL-4 inhibits (1)

A

Th1 differentiation

222
Q

IL-21 promotes _ and inhibits __

A

promotes Th17
inhibits Th1 and Th2

223
Q

development of Th1 subset (

A
224
Q

Th1 cytokines (3)

A
  • IFN gamma
  • TNF (Activates neutrophils, inflammation)
  • IL-10 (inhibitory) - negative feedback
225
Q

functions of IFN gamma (4)

A
  • activate MO
  • activate IgG class switch
  • polarization toward Th1
  • increased expression of TAP, proteasome, HLA-DM, MHC molecules, B7 and amplification of T cell response
226
Q

transcription factors involved in CD8 T cell development (2)

A

Tbet and eomesodermin

227
Q

what is the role of cathepsin B in CTL mediated killing?

A

protects CTLs from their own perforin when it is released

228
Q

what are the two CTL-mediated killing pathways?

A
  • via cytotoxic proteins like perforin and granzyme
  • via Fas- FasL
229
Q

Which complement receptor is exploited by HIV?

A

CR1

230
Q

Which complement receptor binds to EBV?

A

CR2

231
Q

MOA of UNC93B1

A
  • helps with endosomal TLR signaling. (TLR 3, 7,8,9)
232
Q

What is the biochemical function of NADPH oxidase?

A

Convert molecular oxygen to superoxide

233
Q

Which cytokine is a major growth factor for dendritic cells?

A

FLT3LG

234
Q

what is ICOS?

A

ICOS is a T cell receptor required for the development of Tfh

235
Q

classical vs alternative MO pathway

A
  • classical: pro-inflammatory. kill microbes and clear apoptotic cells
  • alternative: tissue repair and fibrosis
236
Q

In regards to donor selection, which is the most favorable donor selection?

A

matched sibling donor from bone marrow

237
Q

The gold standard and most commonly used graft source for HSCT

A
  • gold standard = bone marrow
  • most commonly used = peripheral blood stem cells
238
Q

PFAPA tx (3)

A
  • steroids
  • anakinra
  • tonsillectomy
239
Q

FMF - genetic cause and tx (2)

A
  • MEFV
  • colchicine ppx (decrease risk of amyloidosis)
240
Q

TRAPS - genetics and tx (4)

A
  • TNFRSF1A (AD)
  • steroids
  • anakinra
  • etanercept
241
Q

Mevalonate kinase deficiency (hyperIgD syndrome) - genetics and tx (3)

A
  • MVK
  • steroids
  • anakinra
242
Q

CAPS - genetics and tx (4)

A
  • CIAS1 (AD)
  • anakinra (IL-1 blockade)
  • rilonacept (IL-1 blockade)
  • canakinumab (IL-1 blockade)
243
Q

PAPA - genetics and tx (4)

A
  • PSTPIP1 (AD)
  • anakinra (IL-1 blockade)
  • rilonacept (IL-1 blockade)
  • canakinumab (IL-1 blockade)
244
Q

DIRA- genetics and tx (4)

A
  • IL1RN
  • anakinra (IL-1 blockade)
  • rilonacept (IL-1 blockade)
  • canakinumab (IL-1 blockade)
245
Q

PLAID - genetics and tx (4)

A
  • PLCg2 (AD)
  • avoidance of triggers
  • antihistamines
  • +/- IGRT
246
Q

PFAPA presentation (5)

A
  • regularly recurring fever q3-8 weeks
  • lasts for 3-6 days
  • asx between attacks
  • normal growth and dev
  • exclusion of cyclic neutropenia
247
Q

FMF presentation (6)

A
  • recurrent fever at variable frequency
  • lasts 12h to 3 days
  • sterile peritonitis (abd pain)
  • pleuritis
  • arthritis
  • erysipelas-like rash
248
Q

side effects of colchicine (3)

A
  • GI distress (pain and bleeding)
  • bone marrow suppression
249
Q

Tumor Necrosis Factor Receptor Associated Periodic Syndrome (TRAPS) presentation (9)

A
  • usually adult onset
  • fever can last weeks
  • myalgia
  • periorbital swelling
  • conjunctivitis
  • HA
  • and pain
  • pleuritis with effusion
  • deep, caudally migrating erythematous inflammation
250
Q

Mevalonate Kinase Deficiency presentation (8)

A
  • MVK - involved in cholesterol and steroid synthesis
  • present in infancy
  • fever lasts 3-7 days
  • painful lymphadenopathy
  • aphthous ulcers
  • arthritis/arthralgia
  • erythematous macules or urticaria-like lesions
  • amyloidosis is rare
251
Q

3 diseases that are part of Cryopyrin- Associated periodic syndrome (CAPS)

A
  • CINCA (most severe)
  • Muckle Wells syndrome
  • FCAS (least)
252
Q

does FCAS have postive or negative ice cube test?

A

negative ice cube test but positive evaporative cooling test

253
Q

symptom not present in FCAS but present in CINCA or Muckle-Wells

A

sensorineural hearing loss

254
Q

symptoms present in CINCA but not in Muckle-Wells or FCAS (4)

A
  • bony overgrowth
  • dysmorphism
  • developmental delay
  • leptomeningeal inflammation
255
Q

pyogenic Sterile Arthritis, Pyoderma Gangrenosum and Acne Syndrome (PAPA) presentation (3)

A
  • mutation in CD2 binding protein 1, aka PSTPIP1
  • early in life with arthritis
  • skin issues in teens
256
Q

Deficiency of Interleukin-1 Receptor Antagonist (DIRA) presentation (8)

A
  • due to uninhibited activity of IL-1
  • skin and bone disease
  • neonatal multifocal osteomyelitis
  • rib widening
  • periosteal elevation
  • diffuse osteopenia and osteolytic lesions
  • pustulosis with neutrophilic predominance
  • ABSENT fever
257
Q

PLCg2 associated Ab deficiency and Immune Dysregulation (PLAID) pathophysiology (4)

A
  • AD
  • cold urticaria, Ab deficiency, susceptibility to infections/autoimmunity
  • diminished signaling at physiologic temp (Ab def)
  • enhanced signaling at subphysiologic temp (cold urticaria)
258
Q

diseases that have negative ice cube but positive evaporative test (2)

A

Familial cold-induced autoinflammatory syndrome (FCAS) and PLAID

259
Q

Majeed syndrome (6)

A
  • aka chronic recurrent multifocal osteomyelitis
  • mutation in LPIN2 (lipin 2)
  • childhood onset of fever, bone lesions, and relapsing episodes of pain
  • psoriatic-looking rash and acne
  • congenital dyserythropoietic anemia
  • tx is limited to NSAIDs and steroids
260
Q

Blau syndrome (6)

A
  • GOF NOD2/CARD15 mutation (AD)
  • presents early in life
  • triad of granulomatous polyarthritis, uveitis and pustular skin lesions
  • tx with anti-IL-1 or anti-IL6
261
Q

mutations in Blau syndrome vs Crohn’s disease

A
  • Blau = GOF NOD2
  • Crohn’s = LOF NOD2
262
Q

Deficiency of Adenosine Deaminase 2 (DADA2) pathophysiology (6)

A
  • mutation in CECR1
  • deficiency of ADA2 leads to adenosine accumulation, neutrophil activation, M1 polarization, and inflammatory cytokine production
  • deficiency of ADA1 –> T-B-NK- SCID
263
Q

DADA2 presentation (7)

A
  • fevers
  • recurrent lacunar strokes (typically <5yo)
  • organomegaly
  • cytopenias
  • hypogamm
  • lived reticularis
  • polyarteritis nodosa
264
Q

STING-Associated Vasculopathy with Onset in Infancy (5)

A
  • GOF in TMEM173 that encodes for STING (stimulator of interferon genes)
  • typically dx in the first 8 weeks of life
  • violaceous, scaly lesions that worsen, even becomes necrotic
  • pulmonary complications
  • tx: JAK inhibitors. steroids are not helpful
265
Q

molecules that promote granuloma formation (5)

A
  • ACE
  • calcitriol (1, 25 dihydroxyvitamin D3)
  • osteopontin
  • TNF alpha
  • IFN gamma
266
Q

Lofgren’s syndrome (3)

A
  • self limited, acute form of sarcoidosis
  • triad of b/l hilar adenopathy, erythema nodosum and polyarthritis
  • fever
267
Q

labs for sarcoidosis (4)

A
  • restrictive on PFT
  • IFN gamma predominant cytokine pattern
  • high serum ACE and vit D
  • high CD4/CD8 ratio
268
Q

berylliosis is seen in which pt population?

A

ppl who work with electronics and space industries

269
Q

tissue vs kidney biopsy results of GPA

A
  • tissue: neutrophilic microabscesses rimmed by granulomas and multinucleated giant cells
  • kidney: pauci-immune glomerulonephritis
270
Q

Hyperacute solid organ rejection - mediator, timing, pathophysiology (3)

A
  • mediator: pre-existing Ab
  • timing: minutes to hours
  • Ab to Ag complement activation and endothelial damage, fibrosis
271
Q

acute solid organ rejection - mediator, timing, pathophysiology (3)

A
  • mediator: T cells, PMNs +/- Ab
  • after 7d ~ 3months
  • direct killing by CTLs, cell infiltration and endovasculitis
272
Q

chronic solid organ rejection - mediator, timing, pathophysiology (3)

A
  • mediated by T cells (usually CD4), B cells and cytokines
  • months to years
  • vessel smooth mm proliferation, fibrosis and occlusion
273
Q

acute Ab-mediated solid organ rejection - mediator, timing, pathophysiology (3)

A
  • mediated by alloAb and alloAg (HLA)
  • days to months
  • binding of alloAb to endothelial cell surface triggers local complement, endothelial injury and intravascular thrombosis
274
Q

major functions of IL-2 (2)

A
  • proliferation of Ag-stimulated T and NK cells
  • maintenance of Tregs
275
Q

components of TCR complex (4)

A
276
Q

what is inactive NFkB in the canonical pathway?

A

IkBa/RelA/p50

277
Q

what is the active NFkB in the canonical pathway?

A

RelA/p50

278
Q

what is inactive NFkB in the non-canonical pathway?

A

RelB/p100

279
Q

what is the active NFkB in the non-canonical pathway?

A

RelB/p50

280
Q

steps in activating NFkB via canonical pathway (4)

A
  • ubiquitination of NEMO activates IkkB
  • activated IkkB phosphorylates IkBa and tags it for ubiquitination
  • polyubiquitinated IkBa is degraded
  • remaining RelA/p50 = active form of NFkB that can enter the nucleus
281
Q

a4b7 binds to which surface receptor for gut homing of lymphocytes?

A

MADCAM-1

282
Q

what is C3 nephritif

A
283
Q

what is C3 nephritic factor? (3)

A
  • AutoAb that stabilize C3bBb
  • protects it from degradation by Factor I –> unregulated consumption of C3 and complement activation
284
Q

steps in the Kallikrein contact activation pathway

A
  • Factor XII cleaved to XIIa by contact
  • XIIa cleaves HK-PK complex to kallikrein
  • kallikrein cleaves HK to bradykinin
285
Q

S1P1 for naive T cells in the LN (3)

A
  • S1P1 gradient is higher in blood
  • internalized if recognize Ag-MHC complex (stay in LN longer)
  • reappear in effector T cells (therefore leave LN into circulation)
286
Q

Which cytokines (2) can increase expression of MHC class I molecules on all types of nucleated cells?

A

​​​​​​IFN-a and b
- IFN gamma increases expression of both MHC I and II

287
Q

On which human chromosome is the locus encoding the κ light-chain gene located?

A

Chromosome 2
- λ light-chain locus on chr. 22

288
Q

what guides the rearrangement of the DNA of the genetic segments V, D and J?

A

Recombination Signal Sequences (RSSs)

289
Q

Which enzyme is a lymphoid-specific component of the V(D)J recombinase?

A

RAG-1 and RAG-2

290
Q

What is the defect in MHC class II deficiency?

A

Class II transactivator
- MHC2TA = positive transcriptional co-activator of MHC class II genes
- RFX complex binds to the promoter of the MHC class II genes

291
Q

What is a transcription factor that is very important for dendritic cell development and for cross-presentation?

A

CXCR1

292
Q

The signaling subunit of the pre-BCR is the

A

ITAM containing Igα and Igβ

293
Q

Deficiency of the scaffold protein BLNK arrests B cell development at which stage?

A

Pro-B cell
(BLNK deficiency causes arrest of B cell development in the pro B cell stage since the pre-B-cell stage requires successful signaling via the pre-BCR.)

294
Q

Which cells produce most of the naturally circulating IgM in the blood?

A

B-1 cells
(B-1 cells are innate-like cells that are mostly present in the peritoneal and pleural cavities. constitutively produce IgM without T cell help)

295
Q

Pre-TCR is expressed in which stage of T cell development?

A

Double negative 3

296
Q

α chain locus is rearranged in which stage of T cell development?

A

Double positive

297
Q

The pre-TCR signals constitutively via which signaling molecule?

A

Lck
(The pre-TCR signals constitutively via the cytoplasmic protein kinase Lck. In mice deficient in Lck, T cell development is arrested before the CD4+CD8+ double positive stage and no α chain rearrangement can occur. ZAP-70, expressed early from the double negative stage, is not essential for pre-TCR signaling.)

298
Q

A key initiator of cutaneous inducible innate immunity that is preformed in the cytoplasm of kertinocytes

A

IL-1 alpha

299
Q

the most potent anaphylotoxin

A

C5a

A&I (10 decks)

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