Lecture 2: Viruses II Flashcards Preview

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Flashcards in Lecture 2: Viruses II Deck (76):
1

Viruses to know

Herpes Viruses

Papillomavirus

Smallpox

HIV

2

Important thing about... Herpes Viruses

viral latency

3

Important thing about... Papillomavirus

viruses and cancer

4

Important thing about... Smallpox

vaccines that work

5

Important thing about... HIV

Vaccines that DON'T work

6

Important thing about... HIV

Vaccines that DON'T work

7

2 ways to classify eukaryotic viruses

Baltimore Scheme (1971)

LHT (Lwoff, Horne, and Tournier) system 1962

8

2 ways to classify eukaryotic viruses

Baltimore Scheme (1971)

LHT (Lwoff, Horne, and Tournier) system 1962

9

Baltimore Scheme

group viruses by how mRNA and genome are produced
(ssRNA, etc)

the path to messenger RNA

10

LHT System

categories based on nucelic acid (DNA or RNA)
capsid symmetry (helicle, icosaheral, complex)
presence of envelope
diameter of capsid
number of capsomere

11

LHT System

categories based on nucelic acid (DNA or RNA)
capsid symmetry (helicle, icosaheral, complex)
presence of envelope
diameter of capsid
number of capsomere

12

Baltimore system: 7 families

ds DNA
ssDNA
ds RNA
(+) ss RNA
(-) ss RNA
ssRNA-RT
ds RNA-RT

13

ds DNA

adenoviruses
herpesviruses
poxviruses
papillomaviruses

14

ssDNA (sense strand)

Parvovirus

15

ds RNA

retrovirus

16

(+) ss RNA

Picconaviruses, togaviruses

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(-) ss RNA

a copy will make mRNA
orthmyxoviruses, Rhabdoviruses

18

ss RNA-RT

Retroviruses

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ds RNA-RT

Hepadnaviruses

20

RNA viruses...

Do NOT need to get into the nucleus of the host
Don't need DNA polymerase from host

21

what is in host nucleus that virus may need

DNA polymerase
RNA polymerase

if the virus needs it, it will break in to get it
If it doesn't encode its own DNA polymerases

22

what is in host nucleus that virus may need

DNA polymerase
RNA polymerase

if the virus needs it, it will break in to get it
If it doesn't encode its own polymerases

23

What metabolism goes on in a virion...

NONE
nothing is going on inside the virion
they're inert

24

problem with LHT

based on observation of virions...which are inert and have little to do with what the virus does in the cell

25

problem with LHT

based on observation of virions...which are inert and have little to do with what the virus does in the cell

26

review graph on 9

review graph on 9

27

when do you get to the acute phase?

when the innate immune system didn't do its job right away

28

phenotypes of acute phase

cough
sneeze
sweat/fever

29

what is happening in the accute phase?

immune system being activated

30

which is the phase with no observable phenotype and very few virions outside cell?

ECLIPSE PHASE

31

eclipse phase

no symtoms and no virions seen because the virus is replicating inside the cell

32

eclipse phase

no symtoms and no virions seen because the virus is replicating inside the cell

33

review graph on 10

review graph on 10

34

persistent phase

spike of acute first
viremia subsides
low level of virions observable

HIV

35

Latent virus

acute phase happens
long period of time with no observable virions

Herpes simplex

36

Latent virus

acute phase happens
long period of time with no observable virions

Herpes simplex

37

Alpha Herpesviruses

dsDNA
enveloped
egress

38

Alpha Herpesviruses Simplex I

cold sores

infection of skin, and neurons

39

Alpha Herpesviruses Simplex II

genital herpes

40

other herpesviruses

chickenpox, shingles

41

Where/How herpes infects

epithelial and neural cells (PNS, NOT CNS)
hides in ganglia, traffics to surface, erupts when it infects epithelial cells

42

what causes herpes sores?

immune response to virus

43

stress and herpes

stress induces disease
you become immunocompromised when stressed,
when immune system comes back on after stress, it recognizes the virus and does its job

44

herpes simplex and immune evasion

- infects immunologically privileged cells (neurons--because we dont send the immune system to nerves much so we dont kill them)
- affects antigen presentation... reduces MHC1 on surface
- the infection can persist without virion production (virus turns off all genes when it is just sitting there...until stress happens and immune response weakens)

45

herpes simplex and immune evasion

- infects immunologically privileged cells (neurons--because we dont send the immune system to nerves much so we dont kill them)
- affects antigen presentation... reduces MHC1 on surface
- the infection can persist without virion production (virus turns off all genes when it is just sitting there...until stress happens and immune response weakens)

46

Human Papillomavirus

dsDNA
non enveloped
causes warts, cancer

47

HPV vaccines

Gaurdasil: cervical cancer vaccine, 11-26 year olds (all now, new, better vaccine)

48

HPV causing cancer

two families of it cause 70% of cervical cancers
490,000 new cases of cervical cancer a year, 270,000 deaths... but its a preventable cancer

49

HPV and sex

over 100 genotypes
most common STI, affects 50% of sexually active people in US

50

HPV infection, transmission, and function

infects EPITHELIAL cells
transmitted via contact, even shaking hands can cause warts (not cancer)
TRANSFORMING VIRUS

51

HPV as a TRANSFORMING VIRUS

changes the host cell
can change it to a cancer cell

52

types of HPV

over 150 identified
only like 15 cause cancer... all are mucousal

53

review slide 16 for breakdown of HPV infections

16

54

review slide 16 for breakdown of HPV infections

16

55

what is cancer

abnormal cell growth

56

what causes cancer

mutations

57

what immune response usually deals with cancer

NK cells
kill cancerous cells

58

Cancer and Cell cycle

when DNA damage checkpoints aren't working right, growth can get out of control

59

how a healthy cell becomes cancerous

many different mutations occur over time

initially, mutations happen in checkpoints--which allows other mutations to occur

60

how a healthy cell becomes cancerous

many different mutations occur over time

initially, mutations happen in checkpoints--which allows other mutations to occur

61

late mutations (after mutation at cell cycle check point)

immune evasion
insensitivity to apoptosis (it won't die)
acquisition of own vascular system
ability to colonize other organs
ability to survive hypoxic (low oxygen) conditions

62

late mutations (after mutation at cell cycle check point)

immune evasion
insensitivity to apoptosis (it won't die)
acquisition of own vascular system
ability to colonize other organs
ability to survive hypoxic (low oxygen) conditions

63

Oncogenes

any genes with potential to convert normal cell to cancerous cell

64

Proto-oncogene

cellular gene that can promote cancer if mutated

65

Viral-oncogene

virally encoded oncogene
HPV has 2 of these.... these strains affect E6 and E7 in early stage---messing up checkpoints

66

Papillomaviruses

non enveloped
dsDNA
ancient family... 350 million years old
infect ALL mammals, some birds, reptiles
VERY HOST SPECIFIC

67

Papillomaviruses

non enveloped
dsDNA
ancient family... 350 million years old
infect ALL mammals, some birds, reptiles
VERY HOST SPECIFIC

68

How Papillomaviruses work

increase action of E6 and E7 genes... these inhibit checkpoint proteins PRB and p53

cells go through checkpoint without stopping

E=early genes, L=late genes

69

why does the virus want to skip the checkpoint?

virus needs replicating cells so it can replicate
needs to go through cell division so virus can get access to nucleus

70

what else does the virus do? (HPV)

turns telomere on
immortalization of a cell
cell then replicates uncontrollably and can live forever

71

what else does the virus do? (HPV)

turns telomere on
immortalization of a cell... usually only undergoes replication 180 times
cell then replicates uncontrollably and can live forever

72

HPV life cycle

1) virus enters through breakage of skin from sex... doesn't infect surface cells since they aren't replicating, has to go to cells at bottom

cells at bottom don't produce virions, cells at top do... virions released into mucous

no immune cells in mucous, but thats where they need to be... a little immune evasion

73

effects of HPV genes E6 and E7 blocking checkpoint protiens

promoting faster growth
allowing more mutations indirectly

74

HPV-induced Cervical Cancer is a slow process

it becomes a pro-virus: integrated into chromosome
replicates on chromosome
virus makes no virions when in chromosome... the virus is not being shed BUT
E6 and E7 go through the room, shut off all the checkpoints

75

HPV-induced Cervical Cancer is a slow process

it becomes a pro-virus: integrated into chromosome
replicates on chromosome
virus makes no virions when in chromosome... the virus is not being shed BUT
E6 and E7 go through the room, shut off all the checkpoints

76

Henrietta Lacks and HeLa cells

died of cervical cancer complications in 1952
her cells were first tissue culture cells
first human cells in space
polio vaccine developed on her cells
still used in tons of laboratories today