Quiz 1 Flashcards

1
Q

What are the 5 types of infectious agents?

A

Bacteria
Viruses
Fungi
Parasites
Prions

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2
Q

What is the difference between a commensal organism and a symbiotic organism

A

a commensal organism benefits from close proximity to its host, while the host is unaffected (one-sided symbiosis)

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3
Q

Define immunogenicity

A

the ability of an organism to generate an immune response

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4
Q

What is colonization resistance?

A

the natural phenomena where microbiota inhibits colonization by newcomers

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5
Q

What are the most notable differences between eukaryotic cells and bacterial cells (prokaryotes)?

A
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6
Q

What is the main component of the bacterial cell wall?

A

peptidoglycan

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7
Q

What are two important cell wall polymers found in gram-positive bacteria?

A
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8
Q

What two peptides are commonly found in the peptidoglycan cell wall surrounding bacteria?

A
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9
Q

What are the four most notable components of the outer membrane of gram-negative bacteria?

A
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10
Q

What three elements compose the structure of lipopolysaccharide (LPS)?

A

Lipid A
Core oligosaccharide
O antigen

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11
Q

Which element of the structure of LPS is the endotoxin responsible for fever and shock?

A

Lipid A

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12
Q

Which element of the structure of LPS accounts for the virulence of gram-negative bacteria?

A

O antigen

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13
Q

What are examples of three genus of gram-positive cocci/diplococci?

A

Staphylococcus
Streptococcus
Enterococcus

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14
Q

What are examples of three genus of gram-positive bacilli/rods?

A

Bacillus
Clostridium
Listeria

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15
Q

What is an example of a gram-positive pleomorphic rod?

A

Corynebacterium

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16
Q

What are three examples of gram-negative cocci/diplococci, or coccobacilli?

A

Neisseria
Moraxella
Hemophilus

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17
Q

What are three examples of gram-negative bacilli/rods?

A

E- coli
Klebsiella
Psuedomonas

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18
Q

What are three examples of gram-negative curved/spiral rods?

A

Vibro
Campylobacter
Helicobacter

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19
Q

Why do ureaplasma and mycoplasma not gram stain? What is the clinical significance?

A

they lack a cell wall

they are insenstivie to beta-lactam antibiotics

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20
Q

Mycobacteria can stain gram-positive weakly; what are two notable molecules found in their cell wall?

A

mycolic acids
lipoarabinomannan (LAM) (a glycolipid)

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21
Q

What three antigens serve as the basis for serotyping pathogens?

A

O antigen (LPS)
K antigen (capsule)
H antigen (flagellin)

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22
Q

What is the maximum net yield of ATP in bacteria performing aerobic respiration?

A

36-38 ATP

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23
Q

What is the maximum net yield of ATP in bacteria performing anaerobic respiration?

A

2-36 ATP (can use non-oxygen final electron acceptor)

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24
Q

What is the maximum net yield of ATP in bacteria performing fermentation?

A

2 ATP

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25
Q

How is a bacteria that requires oxygen for metabolism classified?

A

Obligate aerobe

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26
Q

How is a bacteria that can grow with or without oxygen for metabolism classified?

A

Facultative anaerobe

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27
Q

How is a bacteria that can survive with only very little oxygen for metabolism classified?

A

Microaerophilic bacteria

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28
Q

How is a bacteria that is poisoned by oxygen classified?

A

Obligate anaerobe

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29
Q

What three enzymes can play a role in detoxification in aerobic or facultative bacteria?

A

superoxide dismutase
catalase
peroxidase

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30
Q

What is the difference in thickness of the peptidoglycan layer in gram-positive vs gram-negative bacteria?

A

gram-positive- 20-80nm
gram-negative- 5-10nm

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31
Q

Which bacteria are catalase positive?

A

Staphylococci
Pseudomonas aeruginosa
Enteric bacteria
Mycobacterium tuberculosis (at low body T)

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32
Q

What are protein secretion systems?

A
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33
Q

Which protein secretion system type is known as an injectosome or needle-like protein, and is commonly found in Yersinia, Psuedomonas, Salmonella, Shigella, and E. coli?

A

Type III secretion system

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34
Q

What is the major determinant of virulence in virulent strains of bacteria?

A

Exotoxins

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35
Q

T/F: Secretion is the exclusive method of trasmitting exotoxins for bacterial cells

A

F: Exotoxins can also be released by lysis of the bacterial cell in some cases

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36
Q

T/F: Endotoxins are cell-associated substances that are structural components of the peptidoglycan layer of bacterial cells

A

F: Endotoxins are structural components of the outer membrane (LPS) of gram-negative bacteria

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37
Q

Many (not all) bacterial exotoxins have an A-B structure for their components. What are the functions of each subsection?

A

B- binding component that triggers uptake
A- active component that has enzymatic activity

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38
Q

Though there are other types of exotoxins, what are the four major types of exotoxins taught in H&D? Give a short description of each type

A

Enterotoxins- act in GI to cause increased fluid secretion

Neurotoxins- act on nerves to cause paralysis

Pyrogenic exotoxins- stimulate cytokine release (rash, fever, TSS)

Tissue invasive exotoxins- allow bacterial to circumvent cell/tissue barriers

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39
Q

How does a superantigen present itself to T cells? What characterizes the reaction after binding?

A
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40
Q

How are endotoxins secreted from a bacteria into the host during an infection?

A

via cell lysis or detachment (not actively secreted)

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41
Q

Are either exotoxins or endotoxins heat stable?

A
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42
Q

Which part of the LPS structure is most responsible for endotoxin release?

A

Lipid A

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43
Q

What important virulence factor is associated with H antigen?

A

flagella

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44
Q

Bacterial adhesin proteins are most often associated with hair-like fibers called what?

A

pili or fimbriae

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45
Q

Some gram-positive bacteria can form spores. What are three notable facts about spore formation?

A

spores form during a nutrient shortage

spores lack metabolic activity

spores contain dipicolonic acid (granting heat resistance)

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46
Q

Will most antibiotics and hand sanitizers kill spores?

A

No

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47
Q

Does the replication fork in bacterial DNA replication proceed in one or two directions?

A

two directions

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48
Q

By what four processes does bacterial gene exchange occur?

A

Transformation
Conjugation
Transduction
Transposition

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49
Q

What are the three types of bacterial horizontal gene transfer (HGT)?

A
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50
Q

What is meant by labeling a bacteria as “competent”

A

It is able to take up DNA

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51
Q

During bacterial conjugation, the donor cell with the pilus is referred to as F+ or F-?

A

F+

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52
Q

What are transposable elements in bacterial DNA?

A

DNA elements that can jump from one place in bacterial DNA to another, transferring genes or disrupting genes when they insert

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53
Q

What is the main advantage that capsules give to encapsulated bacteria?

A

Protection from opsonization/phagocytosis

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54
Q

Which 5 notable encapsulated bacteria are opsonized and cleared by the spleen?

A

Streptococcus pneumoniae
Hemophilus influenzae
Escherichia coli
Neisseria meningitidis
Salmonella typhi

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55
Q

Peptidoglycan is especially suceptible to what enzyme created by the human body?

A

lysozyme

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56
Q

Bacterial flagella depend on what substrate instead of ATP?

A

protons

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57
Q

What is the general function of quinolone medications?

A

inhibition of unwinding of DNA by DNA gyrase during DNA replication

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58
Q

What virulence factor is presented in the capsule of encapsulated bacteria?

A

K antigen

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59
Q

What important diseases/infections are associated with Streptococcus pneumoniae?

A

Bacterial meningitis
Otitis media
Pneumonia
Sinusitis

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60
Q

What important diseases/infections are associated with Streptococcus agalactiae?

A

Bacterial meningitis

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61
Q

What important diseases/infections are associated with Staphylococcus aureus?

A

Pneumonia
Eye infections
Skin infections
Food poisoning

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62
Q

What important diseases/infections are associated with Streptococcus pyogenes?

A

Skin infections
Upper respiratory tract infections

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63
Q

What important diseases/infections are associated with Psuedomonas aeruginosa?

A

Skin infections
UTI

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64
Q

What important diseases/infections are associated with Escherichia Coli?

A

Food poisoning
UTI

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65
Q

What important diseases/infections are associated with Staphylococcus saprophyticus?

A

UTI

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66
Q

When possible, should bacterial samples be collected before or after administration of microbial agents?

A

before

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67
Q

When would electron miscroscopy be used in direct visualization of bacteria?

A

In order to view bacterial structures

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68
Q

What is the main difference between the Ziehl-Neelson acid-fast staining method, and the Kinyoun acid-fast staining method?

A

Ziehl-Neelson: specimen is heated during staining
Kinyoun: cold acid-fast

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69
Q

What is the color visualized for both acid-fast positive and acid-fast negative bacteria?

A

Acid-fast positive is RED
Acid-fast negative is BLUE
*counterstain is methylene blue

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70
Q

Which types of bacteria undergo alpha hemolysis when plated on a blood agar?

A

Streptococcus pneumoniae
Viridians group Streptococci

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71
Q

What types of bacteria undergo beta hemolysis when plated on a blood agar?

A

Streptoccocus pyogenes
Streptococcus agalactiae
Staphylococcus aureus
Psuedomonas aeruginosa

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72
Q

What notable bacteria undergoes gamma hemolysis (no hemolysis) when plated on a blood agar?

A

Enterococcus faecalis

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73
Q

What two fastidious organisms are selective for chocolate agar?

A

Haemophilus influenzae
Neisseria species

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74
Q

What is a Colistin and Nalidixic acid (CNA) agar selective for?

A

Gram-positive bacteria

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75
Q

What does a MacConkey agar select for? What additional differentiation can it provide?

A

Gram-negative bacteria
It can differentiate lactose fermenters vs. non-lactose fermenters

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76
Q

What color will lactose fermenters turn on a MacConkey agar?

A

pink

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77
Q

What four notable bacteria are lactose fermenters? (CEEK)

A

Citrobacter
Enterobacter
E. coli
Klebsiella

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78
Q

What is the Thayer-Martin media selective for?

A

Neisseria sp.

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79
Q

What is the presentation of a positive catalase test in the lab?

A

Visible O2 bubbles

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80
Q

A rapid agglutination test can be used to identify what type of bacterial infection?

A

Group A streptococcus

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81
Q

The complement system consists of proteases in ________ form?

A

inactive

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82
Q

What are the three anti-microbial functions of complement?

A

Direct destruction of pathogen

Opsonization

Inflammatory response

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83
Q

What are the three pathways of complement activation?

A
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84
Q

What characterizes the Alternative pathway of complement activation?

A

-Activated by exposure to pathogen membranes

-First pathway to act- immediate

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85
Q

What characterizes the Lectin pathway of complement activation?

A

-Activated by mannose-binding lectin (MBL)

-MBL produced by liver during systemic inflammation (24-48 hours post infection)

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86
Q

What characerizes the Classical pathway of complement activation?

A

-Activated by antibodies

-5-7 days after 1st exposure
-immediately after second exposure

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87
Q

What are the three main effector functions of the C3 convertase?

A
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88
Q

What are the main effector functions of the C5 convertase?

A
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89
Q

How do phagocytes (macrophages, neutrophils and eosinophils) detect opsonized targets?

A
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90
Q

What are the three main actions of C3a and C5a in promoting inflammation?

A
  1. Activation of endothelial cells to induce vasodilation and migration of leukocytes into tissue
  2. Increased activation of leukocytes, including mast cell and basophil degranulation
  3. Acting as chemotactic factors
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91
Q

How is the C3 convertase formed in the classical pathway?

A

Components of C1 cleave C2 and C4 to induce the formation of the C3 convertase (C4bC2b)

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92
Q

How is the C3 convertase formed in the lectin pathway?

A

MASP proteases cleave C2 and C4 to induce the formation of the C3 convertase (C4bC2b)

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93
Q

How is the C3 convertase formed in the alternative pathway?

A

Factor D cleaves C3 into C3a and C3b

C3b binds to bacterial surface

Factor D cleaves Factor B to form Bb fragment

C3b and Bb form C3 convertase (C3bBb)

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94
Q

How does C1 INH regulate activation of complement?

A

It is a regulator of C1 in the classical pathway

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95
Q

How do Factors H and I, as well as DAF and MCP regulate activation of complement?

A

They destabilize the C3 convertase in the alternative pathway

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96
Q

How does CD59 regulate the activation of complement?

A

It destabilizies the membrane attack complex (MAC)

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97
Q

What occurs when the pattern recognition receptors (PRRs) on a macrophage or dendritic cell bind a pathogen?

A
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98
Q

What are 5 principle examples of pattern-associated molecular patterns (PAMPs)?

A
  1. LPS
  2. Peptidoglycan
  3. flagellin
  4. Viral dsRNA, ssRNA
  5. Lipoproteins/fungal sugars
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99
Q

What are toll-like receptors (TLRs)?

A

A type of PRR used by immune cells to bind PAMPs

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100
Q

LPS, a major PAMP, is recognized by what receptor/receptor combination?

A

TLR4 paired with CD14

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101
Q

What is the immediate effect of a PAMP binding a TLR?

A

activation of NFkB and cytokine production

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102
Q

What are the 3 most important cytokines in the immune response (for H&D)?

A

IL1, IL6, and TNF

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103
Q

What is the acute phase response?

A

The production of serum proteins by the liver during systemic inflammation?

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104
Q

What are the three major effects of the acute phase response?

A
105
Q

What are two common tests used for systemic inflammation?

A

C- reactive protein (CRP)

Erthryocyte sedimentation rate (ESR)

106
Q

How does IL1 induce fever during systemic inflammation?

A

IL1 -> hypothalamus -> increase COX1, COX2 -> arachidonic acid -> prostaglandins -> fever

107
Q

What cytokine is most associated with septic shock? What is pathology for septic shock?

A

TNF

systemic vasodilation, edema, and loss of organ perfusion leading to organ failure

108
Q

What is the principle anti-viral cytokine?

A

IFNa/B

109
Q

What does IFN-alpha or IFN-beta activate?

A

Natural killer cells

110
Q

NK cells are an early source of what interferon?

A

Interferon gamma

111
Q

What molecules are expressed upon endothelial cell activation?

A

Chemokines (IL8)
Adhesion molecules (selectins and ICAMs)

112
Q

What molecule induces neutrophils to stop rolling and firmly adhere to endothelial cells?

A

LFA-1, a high-affinity integrin

113
Q

Can migration to inflamed tissues occur without chemokines?

A

No

114
Q

Can any inflammatory response be achieved without chemokines?

A

No

115
Q

Can any adaptive immune response occur without chemokines?

A

No

116
Q

What are the four hallmarks of inflammation?

A

Rubor (redness)
Tumor (swelling)
Calor (heat)
Dolor (dolor)

117
Q

What 4 molecules principally activate local capillary endothelium?

A

IL1, TNF, C3a and C5a

118
Q

Which leukocytes are involved in phagocytosis of foreign particles?

A
119
Q

Which leukocytes are involved in degranulation?

A
120
Q

Which leukocytes are involved in extracellular DNA traps?

A
121
Q

Which leukocytes are involved in direct cytotoxicity?

A
122
Q

Which leukocytes are involved in direct cytotoxicity?

A
123
Q

What are the 5 deadliest features of the phagolysosome?

A
  1. Acidification
  2. Oxidative burst (NADPH oxidase)
  3. Nitrosative burst (NO synthase)
  4. Enzymatic degradation (lysozyme, myeloperoxidase, proteases, lipases, etc)
  5. Defensins and other anti-microbials
124
Q

Phagolysosome function is enhanced in the presence of what interferon?

A

interferon gamma

125
Q

What three enzymes do bacteria often employ to counterbalance the effects of an oxidative burst?

A

Superoxide dismutase
catalase
peroxidase

126
Q

Granules secreted by NK cells contain what two notable molecules?

A

Perforin
Granzyme B

127
Q

Deficiences in complement are most closely associated with suceptibility to what kind of infection?

A

Neisseria meningitidis infection

128
Q

How does ia Factor H/I deficiency lead to an increased suceptibility to Neisseria meningitidis infection?

A

Loss of negative regulation of complement leads to constant over-activation and over-consumption of C3

129
Q

Deficiencies in C1, C2, C4 or MAC lead to increased suceptibility to what kind of infection?

A

Neisseria mengitidis infection

130
Q

What are two notable syndromes associated with complement deficiency?

A

Paroxysmal noctural hemoglobinuria (PNH)

Hereditary angioedma (HAE)

131
Q

What are the clinical presentations of hereditary angioedema?

A

Rapid swelling of hands, feet, limbs, face, and GI tract due to overproduction of bradykinin, caused by loss of or misfunction of C1 INH

132
Q

What characterizes Chronic granulomatous disease?

A

defective NADPH oxidase

133
Q

What characterizes Chediak-Higashi syndrome?

A

Mutations in CHS1 (LYST) gene impairing trafficking of granules and vesicles, including failure to form functional phagolysosomes

134
Q

What characterizes Leukocyte adhesion deficiency?

A

Loss of LFA-1

135
Q

How does SARS CoV-2 inhibit the innate immune system?

A

Inhibition of cytoplasmic pattern recognition
Inhibition of NFkB or IRFs
Inhibition of production of IFNa/B
Interruption of cytokine signaling

136
Q

Where does central tolerance occur in the body? What two processes occur to promote central tolerance?

A
137
Q

Where does peripheral tolerance occur in the body?

A

Circulating T cells

138
Q

An activated DC (+ signal 2) has what effect on circulating T cells as a function of peripheral tolerance?

A
139
Q

An inactivated DC (no signal 2) has what effect on circulating T cells as a function of peripheral tolerance?

A
140
Q

What two roles do Treg cells play in peripheral tolerance?

A

Convert activated DCs into regulatory DCs

Secrete immunosuppressive cytokines IL-10, and TGF-beta

141
Q

Treg cells are regulated by what transcription factor?

A

FoxP3

142
Q

What condition results from FoxP3 mutations?

A

Immunodysregulation polyendocrinopathy enteropathy X-linked syndrome (IPEX)

143
Q

Why is a complete loss of function in FoxP3 likely not observed?

A

It would leadto overwhelming autoimmunity resulting in death

144
Q

Which two types of hypersensivity reactions are mediated by IgG?

A

Type II (cell-associated antigens)
Type III (antigen immune complexes)

145
Q

Which type of hypersensitivity reactions are mediated by IgE?

A

Type I (allergic reactions)

146
Q

Which type of hypersensitivity reaction is mediated by T cells?

A

Type IV

147
Q

What are the three major reasons that tolerance mechanisms break down?

A

Genetics
Environmental factors
Infectious history

148
Q

What elements of genetics can contribute to breakdown of tolerance mechanisms?

A

HLA mutations (most important)
Sex
Immunoregulatory genes

149
Q

What environmental factors can contribute to breakdown of tolerance mechanisms?

A

Smoking, weight, age, diet, etc

150
Q

What elements of infectious history can contribute to breakdown of tolerance mechanisms?

A

similarity between foreign and self antigens (i.e. molecular mimicry)

151
Q

What is the signifiance of the HLA-B27 allele in context of hypersensitivity reactions?

A

Its association with:
psoriasis
ankylosing spondylitis
IBD
reactive arthritis

152
Q

Are males or females more suceptible to hypersensitivity reactions (especially in 3rd, 4th, and 5th decade of life)?

A

Females

153
Q

To what two types of antigens can hypersensitivty reactions be directed?

A

Foreign antigens
Self antigens

154
Q

What is the general role of Tregs?

A

To suppress harmful immune responses through direct supression of APCs and secretion of immunosuppressive cytokines (IL-10 and TGF-beta)

155
Q

Do autoimmune diseases tend to be single gene dysfunctions or results of complex genetic and environmental factors?

A

Complex genetic and environmental factors, though single gene dysfunctions also occur

156
Q

What is the target of aminoglycosides in bacterial cells?

A

the 70S ribosomal subunit

157
Q

What is the action of quinolone antibiotics on the bacterial cell?

A

They inhibit the unwinding of DNA by DNA gyrase

158
Q

What element of the immune response is found to be highly enriched in mucus?

A

defensins

159
Q

Of the major inflammatory cytokines (IL1, IL6, and TNF) which is responsible for triggering the acute phase reaction?

A

IL6

160
Q

Of the major inflammatory cytokines (IL1, IL6, and TNF) which is responsible for triggering septic shock?

A

TNF

161
Q

Of the major inflammatory cytokines (IL1, IL6, and TNF) which is most responsible for triggering fever?

A

IL1

162
Q

Of the major inflammatory cytokines (IL1, IL6, and TNF) which are responsible for phagocyte activation?

A

IL1, IL6, and TNF

163
Q

Of the major inflammatory cytokines (IL1, IL6, and TNF) which is responsible for activating endothelial cells?

A

IL1 and TNF

164
Q

Is increased hematopoeisis a result of the local or systemic immunologic response?

A

Systemic effects (GM-CSF, G-CSF)

165
Q

What are the main results of the acute phase response?

A

Increased in complement factors C3, Factor B, C9, etc

Increased pathogen recognition (MB-Lectin, C-reactive protein)

Increased coagulation

166
Q

What types of pathogens are Type I interferons (IFN a, IFN b) specific for?

A

Viral pathogens

167
Q

What is the main function of IFNa/B?

A

activating natural killer cells

168
Q

What major function do NK cells utilize in addition to directly killing virally infected cells?

A

Acting as an early source of IFN gamma

169
Q

What is the immediate result of endothelial cell activation (by C3a, C5a)?

A

expression of adhesion molecules (ICAMs, selectins, addressins)

vasodilation

170
Q

What effect does interferon gamma have on phagolysosome function?

A

It enhances it

171
Q

Secretory granules used by NK cells to kill infected targets contain what 2 notable molecules?

A

Perforin
Granzyme B

172
Q

What disease is characterized by an inability to make glycosylphosphatidylinositol (GPI) anchors, leading to intravascular hemolytic anemia and thrombosis?

A

PNH

173
Q

What are four parameters in the definition of systemic inflammatory response syndrome (SIRS)?

A

Temperature
Heart Rate
Respiratory Rate
WBC count

174
Q

What is the main difference between molecule binding in B cells and T cells?

A

B cells can bind soluble, free-floating antignes (almost anything)

T cells can only bind small, peptide antigens presented by MHC

175
Q

How small are the peptide antigens that MHC can present to T cells?

A

8-20 AA long peptides

176
Q

CD8+ T cells are activated by which MHC class?

A
177
Q

CD4+ T cells are activated by which MHC class?

A
178
Q

What are the three MHC class I genes?

A

HLA-A
HLA-B
HLA-C

179
Q

What are the three MHC class II genes?

A

HLA-DP
HLA-DQ
HLA-DR

180
Q

All nucleated cells express which MHC class?

A

MHC class I

181
Q

Professional antigen presenting cells (macrophages, DCs, B cells) express which MHC class?

A

MHC class II

182
Q

Which subunits comprise the structure of the MHC class I molecule?

A
183
Q

Which subunits comprise the structure of the MHC class II molecule?

A
184
Q

Which subunits comprise the structure of the MHC class II molecule?

A
185
Q

Which genes are the most polymorphic in the human genome, with over 15,000 polymorphic variants?

A

MHC genes (HLA locus)

186
Q

Cytosolic antigens (often from viruses) are more likely to be presented by which MHC class?

A

MHC class I

187
Q

How are antigens attached to the MHC class I receptor? How does the receptor end up on the cell surface?

A
188
Q

What is significant about the binding of CLIP to MHC class II molecule? Why is binding of HLA-DM to MHC class II significant?

A

CLIP prevents binding of peptides to MHC

HLA-DM binding to MHC class II releases CLIP, allowing peptides to bind and MHC class II molecule to travel to the surface

189
Q

What is cross-presentation? What cell holds this function?

A
190
Q

What is the purpose of the variable region of an antibody?

A

antigen recognition

191
Q

What is the purpose of the constant (Fc) region of an antibody?

A

Effector functions like complement activation and opsonization

192
Q

How many unique antigens receptors are expressed by a naive or resting B cell?

A

1

193
Q

Which antibody is associated with mast cell/eosinophil activation?

A
194
Q

Which antibody is not secreted, but is expressed on surface of naive B cells along with IgM?

A
195
Q

Which antibody is the earliest produced, can activate complement, and participate in neutralization of pathogens?

A
196
Q

Which antibody can activate complement, particpate in neutralization of pathogens, opsonization, ADCC, and is the most prevalent in serum?

A
197
Q

Which antibody can participate in neutralization reactions and is associated with mucosal surfaces?

A
198
Q

T/F: Antibodies are limited to binding protein structures only

A

False

199
Q

The B cell receptor is associated with adaptor molecules that use what intracellular signals?

A

Ig-alpha and Ig-beta

200
Q

The T cell receptor is associated with adaptor moelcules that use what intracellular signals?

A

CD3 (multiple subunits)

201
Q

What is the signifiance of IL-7? What is the result of deficient IL7 signaling?

A

IL7 is important for lymphoid commitment

202
Q

What is the role of RAG recombinase in DNA recombination?

A
203
Q

What is the role of TdT during DNA recombination?

A
204
Q

How many heavy and light chain loci exist for antibodies?

A

2 light chain loci (4 alleles)
1 heavy chain loci (2 alleles)

205
Q

X-linked agammaglobulinemia is a defect in what kinase?

A

Bruton’s Tyrosine Kinase

206
Q

What is the role of Bruton’s Tyrosine Kinase (Btk)?

A

To signal that productive antigen receptor is present at the cell surface of pre-B cells

207
Q

What effect does a Btk deficiency have on positive selection for B cells?

A

Positive selection fails due to lack of signaling -> apoptosis

208
Q

What are part 1 and part 2 of positive selection for T cells? Where do these processes occur?

A

1- Productive TCR rearrangement/expression
2- Recognition of host MHC by TCRs

the cortex of the Thymus

209
Q

Where does negative selection occur for T cells?

A

The medulla of the thymus

210
Q

What rough percentage of thymocytes die due to a failure to recognize self MHC (positive selection part 2)?

A

95-99%

211
Q

What important ligand is associated with High endothelial venules (HEVs)?

A

L-selectin

212
Q

Traffick to T cell and B cell zones is driven by what kind of molecules?

A

cytokines

213
Q

What is Common Variable Immunodeficiency (CVID)?

A

A group of variable defects in antibody response; loss of one, some , or all isotypes

214
Q

What is the most common subtype of CVID? What are common signs/sx? What are two increased disease risks for CVID patients?

A
215
Q

In addition to PRR-induced activation, what cytokines are used to activate DCs during an infection?

A
216
Q

Given the following diagram, a deficiency in LFA-1 or ICAM-1 could have what effect on the immune system?

A

Impaired activation of naive T cells by dendritic cells

Also, could effect the ability of neutrophils to transmigrate through capillaries to site of infection

217
Q

What 3 signals are needed for T cell activation?

A
  1. TCR signaling
  2. Costimulation
  3. Cytokine-induced effector differentiation
218
Q

What composes the TCR signaling (signal 1) component during T cell activation?

A

TCR + pMHC +co-receptor (CD4 or CD8) + CD3

219
Q

What composes the costimulation (signal 2) component during T cell activation?

A

B7:CD28
B7.1 = CD80
B7.2 = CD86

220
Q

What are the two negative costimulatory signals that are expressed after T cell activation?

A

CTLA-4
PD-1

221
Q

How does CTLA-4 compete with CD28 to bind to B7?

A

It binds with higher affinity; competitive inhibition

222
Q

What constitutes the cytokine component (signal 3) of T cell activation?

A

Various (IL-12 is notable), which can be supplied by antigen-presenting cells (APCs) and other cell types

223
Q

What is significant to know about TCR signaling?

A

1: Activation of TKs (ZAP-70)
2: Ca2+ dependent activation of NFAT
TK-dependent activation of NFkB & AP-1

224
Q

What are the overall roles of NFAT, NFkB, and AP-1?

A
225
Q

What is the most specific significant action in T cell clonal expansion triggered by NFAT, NFkB, and AP-1?

A
226
Q

What signal 3 cytokine induces Th1 cell differentiation? What cytokines does Th1 preferentially release?

A
227
Q

What signal 3 cytokine induces Th2 cell differentiation? What cytokines does Th2 preferentially release?

A
228
Q

What signal 3 cytokine induces Th17 cell differentiation? What cytokines does Th17 preferentially release?

A
229
Q

What signal 3 cytokine induces Treg cell differentiation? What cytokines does Treg preferentially release?

A
230
Q

What effector functions are the most important for Th1 cells?

A

Enhancing the microbial activity of macrophages
(CD40/CD40L pathway)

231
Q

What effector functions are the most important for Th2 cells?

A

IL4, IL13 pathway: Alternatively activated macrophages (M2)

IL5 pathway: Activation of eosinophils and mast cells

232
Q

What effector functions are most important for Th17 cells?

A

IL17: Increased neuotrphils

IL 22: Increased mucosa-associated defenses

233
Q

What effector functions are most important for Treg cells? When do the chiefly arise?

A

Mostly IL10, TGF-beta mediated immune suppression

They mainly arise
1) during thymic selection
2) during T cell responses to foreign pathogens

234
Q

What type of T cell is responsible for helping to enhance B cell activation?

A

T follicular helper cells (Tfh)

235
Q

By what mechanisms do Tfh cells enhance B cell activation?

A
236
Q

What two critical processes in the germinal center are initiated by Activation-induced deaminase (AID)?

A
237
Q

What is the main benefit of isotype class switching in B cells?

A

The ability to switch to producing a specific antibody type more relevant to the pathogen/antigen exposure

238
Q

What is the end goal of somatic hypermutation?

A

To produce a higher level of antigen binding specificity/affinity

239
Q

What is Affinity maturation?

A

Multiple rounds of somatic hypermutation with the goal of producing higher level of antigen binding specificity/affinity

240
Q

What specific cell type is especially important to enhance the process of affinity maturation?

A
241
Q

Can the germinal center occur without Tfh cell migration into the B cell follicle?

A

No

242
Q

Which antibody types can participate in neutralization of pathogens?

A
243
Q

Which antibody types can participate in opsonization of pathogens?

A
244
Q

Which antibody types can participate in complement activation?

A
245
Q

Which antibody types can participate in mast cell activation?

A
246
Q

What is the primary site of VDJ recombination in developing B cells?

A

the lymph node

246
Q

Which antibody types can participate in antibody-dependent cell-mediated cytotoxicity (ADCC)?

A
247
Q

Which antibody isotype can most readily cross the placenta?

A

IgG

248
Q

Which viruses are double-stranded DNA viruses?

A

Herpes viruses

249
Q

Which MHC allele is notable for a link between its mutation and psoriasis, anklyosing spondylitis, IBD, and reactive arthritis?

A

HLA-B27

250
Q

Which immunosuppressive cytokines are principly secreted by Tregs?

A

IL-10 and TGF beta

251
Q

Which type of cell drives T1 hypersensitivty reactions?

A

Th2 cells

252
Q

The first exposure (sensitization) of a T1 hypersensitivity reaction involves what two actions by Th2 cells?

A
253
Q

What occurs during second exposure of a T1 hypersensitivity reactions?

A

Mast cell degranulation triggered by antigens binding IgE

254
Q

What molecule is responsible for vasodilation and bronchoconstriction in the early phase allergic reactions (within minutes)

A
255
Q

What two types of molecules are responsible for local and systemic reactions as part of the late phase allergic reaction (8+ hours)?

A

Cytokines (IL4, IL5, TNF)

Leukotrienes

256
Q

The early phase of an allergic reaction is driven by what molecule? What are common symptoms?

A

Histamine (induces vasodilation)

Urticaria, edema, rhinintis, asthma

257
Q

The late phase of an allergic reaction is driven by what molecules?

A

Leukotrienes and cytokines

258
Q

What are the go-to treatments for allergic reactions (especially anaphylaxis)?

A

Epinephrine
Anti-histamines
Corticosteroids
Albuterol