EBV, CMV, Viral Latency, and Cancer Flashcards
1
Q
acute lytic infection
A
- viral infection that results in the production of progeny virus and lysis of the infected cell
2
Q
acute lytic viral infections - initial infection event is followed by
A
- rapid, often exponential replication of the virus
3
Q
acute symptoms of lytic viral infections due to
A
- tissue destruction due to virus replication
- side effects of host immune response
4
Q
chronic lytic viral infection
A
- productive viral infection in a subset of cells
- continual infection/re-infection cycle
- ongoing shedding of virus from infected cells that does not immediately result in lysis.
5
Q
types of chronic lytic infections
A
- chronic focal infection
- chronic diffuse infection
6
Q
chronic focal infection
A
- a new subset of carrier cells produces virus
- infects neighboring cells
- initial cells replaced by new cells
- newly infected cells reinstate the process
7
Q
chronic diffuse infection
A
- both infected cells and virus continue to replicate
- cells are not lysed by virus
- cells continue to shed virus for their life span
8
Q
hepatitis C causes what kind of infection?
A
- chronic lytic infection
9
Q
what type of replication does hepatitis C virus have
A
- persistent lytic replication
10
Q
result of hepatitis C virus
A
- culminates in cirrhosis and/or hepatocellular carcinoma
11
Q
the main difference between acute lytic and chronic infection is
A
- the time to clear the virus
12
Q
acute infection time to clear the virus
A
- less than two weeks
13
Q
chronic infection time to clear the virus
A
- weeks/months/years
14
Q
what is latency in a virus?
A
- presence of viral nucleic acid in the absence of pre-formed infectious virus that has the ability to re-initiate lytic replication
15
Q
the difference between chronic versus latent infection
A
- difference is in the molecular state of the virus
16
Q
production of virus in latent infection
A
- latent infections do not produce infectious virus
17
Q
product of virus in chronic infection
A
- chronic infections involve continual production of new viral particles
18
Q
what is the viral genome maintained as in all latent viruses
A
- DNA
19
Q
provirus
A
- viral genome integrated into host genome
20
Q
episome
A
viral genome maintained as extra chromosomal DNA
21
Q
EBV is in what virus family?
A
- herpesvirus 4
22
Q
DNA in herpesvirus
A
- linear dsDNA
- in icosahedral core
23
Q
virus particle in herpesvirus
A
- enveloped in lipid membrane
24
Q
where does the lipid membrane come from in herpesvirus?
A
- lipid comes from the host cell
25
where is EBV's site of latency
- lymphoid cells
26
where is CMV's site of latency
- various cells
27
EBV transmitted by
- saliva
28
EBV initially infects
- epithelial cells in oropharynx
29
EBV spreads to
- blood
| - infects B-cells via CD21 complement receptor
30
primary infection in EBV
- asymptomatic
31
when is EBV clinically apparent as infectious mono
- when primary infection occurs later in adolescents and young adults
32
clinical signs and symptoms of infectious mononucleosis
- fatigue
- fever
- sore throat
- lymphadenopathy
33
mononucleosis is the proliferation of
- mononuclear cells
| - lymphocytes
34
infected B cells are recognized as
- atypical lymphocytes by cytotoxic T cells
35
immunologic test in EBV
- heterophiles antibodies
36
heterophile antibodies used
- define antibodies against poorly-defined or cross reacting antigens
37
how is EBV tested
- monospot test
| - does not confirm infection
38
EBV specific antibodies
- IgM - early
- IgG - later
- VCA - viral capsid antigens
39
treatment of EBV
- acyclovir not effective
| - no vaccine
40
EBV associated diseases
- life-threatening mono in children with X-linked lymphoproliferative syndrome
- hairy leukoplakia
- burkitt's lymphoma
41
hairy leukoplakia symptoms
- whitish, nonmalignant lesions on the tongue
42
hairy leukoplakia found in which population
- immunocompromised patients, specially AIDS
43
Burkett's lymphoma endemic in
- Africa
| - New Guinea
44
Burkett's lymphoma sporadic in
- US
| - Western Europe
45
Burkett's lymphoma associated with
- HIV
46
EBV latency
- establishes latency as episomall DNA in nucleus of infected B cells
- ONLY INFECTS B cells
47
latently infected cells produce
- IL-10 resulting in uncontrolled proliferation
48
two groups of genes mutated in cancer
- tumor suppressors
| - proto-oncogenes
49
activity of tumor suppressors
- inhibit cell cycle progression
50
mutation in tumor suppressors
- loss of function
51
examples of tumor suppressors
- Rb
- p53
- p16
- ARF
- PTEN
52
porto-oncogenes activity
- stimulate cell cycle progression
53
mutation in cancer of proto-oncogenes
- gain of function
54
proto-oncogene is (wild type/mutant)
- wild type
55
oncogene is (wild type/mutant)
- mutant
56
examples of proto-oncogenes
- cyclin D1
- Mdm2
- myc
- ras
57
more divisions in EBV infected cells means
- more chances that unlikely mutations occur
58
CMV transmitted by
- transplacentally
- saliva
- genital secretions
- transfusions
- transplants
59
CMV on smear
- giant cell formation with intranuclear inclusions
| - looks like owl eyes
60
most common cause of congenital abnormalities in the US
- CMV
61
CMV symptomatology for primary infections in kids and adults
- asymptomatic
62
CMV in 1st trimester of pregnancy
- cytomegalic inclusion disease causes defects in many organs
63
latently infected cells by CMV
- have unstable MHC1
| - aren't well recognized by CD8 T cells
64
CMV skin findings
- blueberry muffin lesions in neonates
65
heterophiles test in CMV
- heterophiles negative mono in immunocompetent individuals
66
symptoms of CMV in transplant patients
- pneumonia
- esophagitis
- hepatitis
67
infection of CMV in AIDS patients
- intestinal infections
- severe colitis
- diarrhea
- retinitis
68
CMV treatment
- ganciclovir and valgancyclovir
| - no vaccine
69
why are heterophiles antibodies associated with infectious mono in EBV but not CMV
- EBV infects B cells which makes a lot of antibodies not specific for the virus
- CMV infects a host of cells
70
why does acyclovir not work well against EBV infection
- acyclovir must be activated by viral thymidine kinase
| - only in infected cells
71
ganciclovir is activated by
- cellular kinase
