Viral Pathogenesis Flashcards Preview

Jason's Respiratory Block > Viral Pathogenesis > Flashcards

Flashcards in Viral Pathogenesis Deck (90):
1

3 ways for viruses to be maintained in nature?

1. shed into environment
2. vector: insect, needle
3. congenitally

2

a systemic viral infection is worse than a local ? T/F?

False. Not correlated with severity

3

Explain tropism

anatomical localization of infection (initially determined by receptor specificity

4

What's parenteral inoculation?

via mosquito or bite

5

What determines initial site of virus deposition in the airways? Explain

droplet size.
>10um= nose
5-10um = airways
<5um = alveoli

6

What the body temp in nose vs. lung bases?

33 degrees nose
37 degrees lung bases

7

Rhinovirus spreads from initial site?

Nope. localised

8

3 viruses that spread from infection site?

MMR baby. and varicella

9

3 viruses that stay localised?

rhino
influenza
resp syncytial virus (RSV)

10

What kind of cytopathic effect could RSV have on lungs?

presence of giant cells

11

How does measles infect you?

breath it in
replicate in epithelials of URT
infects Macros, lymphos, DCs into lymphnodes
circulate and amplify and go back to lungs and mouth

12

How are HIV and measles similar?

both cause immunosuppression

13

What are koplick spots?

measles initial replication causes aggregations of lymphocytes

14

T/F? Viruses that infect GI have an envelope for more protection?

FALSE YO! are acid and bile resistant, no envelope

15

What does rotavirus cause?

diarrhea

16

two viruses that infect GI but spread

Hep A
polio

17

HIV and Hep B don't have receptors for epithelial cells, how would they enter?

abrasions/breach via rectal route

18

What's an M cell?

kinda like a DC cell but in the GI, they're the sentinels in the GI sampling and presenting to underlying lyphoid tissue

19

how many shells does rotavirus have? why?

triple shelled to withstand the GI environment

20

What does rotavirus do to you?

infects GI, destroys M cells, epithelial cells, inflammation, gastroenteritis

21

Rota virus causes diarrhea, how is it amplified or dangerous to children?

dehydration
NSP4 protein increases fluid secretion

22

What's the difference between primary and secondary viremia?

primary: in circulation amplifying
secondary: reaches target tissues

23

Name a systemic virus that infects meninges

enteroviruses

24

Name a systemic virus that infects CNS

polio
coxsackie

25

Name a systemic virus that infects skin

group A coxsackie (hand/foot/mouth)
echovirus

26

Name a systemic virus that infects muscle

Group B coxsackieviruses

27

What virus enters transcutaneously?

papillomavirus
HepB,C,HIV

28

What viruses from insect/animal bites?

dengue virus - fever, rash, poly arthritis

29

conjunctiva route is rare, what viruses can enter this way?

adenovirus
enterovirus 70
HSV

30

What's the mechnism of spread of a virus?

epithelium
lymph capillary
vein
lymph node
circulation

31

in primary viremia, where is the virus

free in plasma

32

in secondary viremia, it infects vascular endothelium or release in large amount from what two organs?

liver
spleen

33

How is viremia managed by the immune system? how long?

macrophages to the rescue! take 1-2 weeks

34

What is cell-associated viremia?

spread via the immune system
HIV - CD4
measles/dengue: monocytes

35

what does smallpox do to a fetus?

it's cytocidal, death and abortion

36

what do non cytocidal viruses do to foetuses? 2 examples?

developmental abnormalities: rubella, cytomegalovirus

37

what can infect a baby in the birth canal? 4 things:

herpes simplex, varicella, CMV
coxsackie B from faeces

38

What does congenital rubella syndrome do?

slows down cell division

39

4 consequences of congenital rubella syndrome?

1. microcephaly
2. heart defects
3. cataracts
4. deafness

40

How does polarized release determine tropism of viruses?

those viruses that prefer apical release are less likely to infect deep layers

41

What virus needs tryptase from Clara cells?

influenza

42

what is a cytocidal virus? 2 examples

death from direct viral replication
1. rotavirus
2. poliovirus

43

what can rhinovirus do to lungs in terms of affecting their function?

cilial stasis can predispose to second bacterial infection

44

What is immunopathology in terms of viruses?

immune system collateral damage

45

2 kinds of antibody mediated pathology:

1. Ab-dependent enhancement of infection
2. antigen-Ab complexes

46

What is Ab-dependent enhancement of infection? example?

Dengue hemorrhagic, infects macrophages

47

What is antigen-Ab complexes? how is it bad?

big ass complexes deposit in kidney causing glomerulonephritis/vasculitis

48

what can cause antigen-Ab complexes?

Hep. B

49

Measles rash is cause by what mediated pathology?

CD4 T-cell-mediated responses

50

CD4 T-cell-mediated responses for viral immunopathology. What happens?

Cytokines and eosinophils recruitment can cause bronchiolitis in infants with RSV

51

What is RSV?

respiratory syncytial virus

52

What virus causes CD8 T-cell mediated responses?

Hep B.

53

HepB does what in terms of CD8 T-cell mediated response?

hepatocyte lysis

54

What are signs of liver damage in hep B?

yellow eyes, skin

55

How does the eyes and skin turn yellow in liver damage with Hep B?

excess bilirubin in tissues as it's not secreted into bile from old heme

56

Can viruses cause autoimmunity? how?

yes via molecular mimicry

57

2 examples of a virus mediated autoimmunity?

Guillain-Barre syndrome for nerves
coxsackie B4 for heart muscle

58

What Interleukin does measles suppress?

IL-12

59

What does Type 1 IFN a/B mainly target? what does it activate?

target dsRNA viruses
NK cells

60

What does Type 2 IFN-y come from? what does it do?

made by NK cells
enhance MHC class I and II
activated Macros

61

How would a virus evade T or B-cells? examples?

Latency
HSV in T-cells
EBV in B-cells

62

How would a virus evade antibodies? examples?

antigenic drift like flu and HIV

63

How would a virus evade T-cell recognition? 3 things

antigenic variation
inhibit viral peptide presentation
decrease MHC class I (HIV, RSV, adeno)

64

How does viral antigenic drift happen?

spontaneously through RNA errors

65

How would HIV evade CD8 recognition?

induces endocytosis of MHC class I and mess with the CTL epitope

66

What viral protein binds to cytosolic side of TAP transporter to evade CD8?

HSV (herpes simplex)

67

What viral protein binds to luminal side of TAP transporter to evade CD8?

CMV

68

What is TAP?

transporter of antigen and peptides

69

What does adenovirus do to MHC peptide complex?

anchors in the ER so it can't do diddly squat

70

what virus inhibits proteosomes?

EBV

71

Is NK cell a B-cell? or a T-cell?

Neither, own distinct lineage

72

NK cells are a major source of what?

IFN-y

73

What cytokines activated NK cells?

IL-12
IFNa/b

74

I'm getting a lot of varicella and CMV infections... what's up doc?

you might have a NK cell deficiency

75

NK cells are part of innate or adaptive immune system?

innate

76

Do NK cells need an antigen to activate?

Nope, could be stress protein or heat shock proteins too

77

How many signals do NK cells need to kill?

Two
1. first is the check
2. 2nd is the inhibitory (without it, it will kill)

78

NK cell inhibitory receptor binds to what?

MHC class I of target cell

79

What happens to viruses that cause reduction of MHC class I expression?

evade CD8 but more susceptible to NK killing

80

What virus encodes an MHC class I-like molecule to avoid NK cell killing?

Human CMV cytomegalovirus

81

What is PKR? how is it activated?

activated by IFN, helps to inhibit translation of viral proteins

82

What does PKR need to be activated? 2 things

viral dsRNA (long enough)
autophosphorylation

83

what is a viral evasion technique to get around IFN and PKR? which viruses?

abundant small bits of RNA that bind to PKR but not lengthy enough to activate PKR
EBV/adenovirus

84

What does vaccinia and reovirus do to avoid PKR activation?

Virus proteins bind to dsRNA to prevent PKR activation

85

What competes with PKR for eIF2a activation to stop viral translation of proteins?

Vaccinia

86

If you are resistant to HIV, what could be causing it?

You may be missing the CCR5 secondary binding receptor

87

What Ig class are viruses susceptible to?

IgA

88

4 kinds of genetic factors influencing susceptibility to viral infections?

inherited defects (no Ig class)
MHC polymorphisms
interferon-inducible genes
receptor genes

89

4 kinds of non-genetic factors influencing susceptibility to viral infections?

Age
malnutrition
preg/hormones/males
dul infections

90

4 outcomes of viral infections

fatal
full recovery
recovery but permanent damage
persistent infection