Lymphotropic Herpesviruses Flashcards by jenny Guo

what are examples of beta herpesviruses

CMV
herpesvirus 6a
herpesvirus 6b
herpesvirus 7

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what are examples of gamma herpesviruses

epstein barr virus

Kaposi’s sarcoma virus

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What is a special feature of gamma herpesviruses?

can be oncogenic

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what do cells infected with CMV look like?

owl eyes–inclusion bodies

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% seropositive for CMV in US

40-80%

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what kinds of disease does CMV cause

healthy adults: asymptomatic, mild mononucleosis or cold-like symptoms

symptomatic with immunosuppresion

long term persistent infec associations w/ atherosclerosis, immunosenescence, neuroblastoma

leading cause of congenital birth defects

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genome of CMV

double stranded DNA

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CMV size

200 nm

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how many proteins does CMV encode

more than 750

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DNA replication machinery of CMV

CMV has its own

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shape of CMV

envelope or not

icosahedral
has envelope w/ glycoproteins
has tegument proteins and RNA inside

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what are the stages of transcription for CMV?

immediate early
early
late

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CMV is transmitted how

direct contact w/ secretions that have virus (semen, cervical secretions, blood, saliva, tears, breast milk, urine, feces)

inoculation onto a mucosal site

organ transplants, transplacental

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what symptoms are seen when CMV sheds?

can have or not have symptoms

viral excretion starts at 1 month

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in whom do you see the highest rates of transmission?

parents of CMV shedding child who goes to daycares

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Where does CMV lytic replication occur?

in epithelial, dendritic, fibroblasts, sm musc, endothelial, macrophages, trophoblasts

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where is CMV latent in?

CD34+ hematopoietic progenitor cells, monocytes

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role of innate immune response in CMV infection?

can control but not enough to clear

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role of humoral response in CMV infec

no role in clearance, but may limit reinfec or reactivation

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role of cell mediated immunity in CMV infec

cytotoxic T cells kill CMV infected cells

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ultimate result of immune reaction in CMV infection

cannot completely control CMV

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symptoms of CMV in healthy adults, children

mild, often unapparent

fever, fatigue, sore throat, headache

liver fxn abnormalities

lymphocytosis (increase in # of lymphocytes and atypical lymphocytes)

lymphadenopathy

mononucleosis (hterophile antibody negative)

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how do you diagnose CMV

serology-IgM, IgG–IgG avidity increases over time and can distinguish recent or past infec

Owl’s eye cells in urine

culture virus, immunofluorescence detect.

PCR!!

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treatment for CMV infections

note: don’t work for latent infections

ganciclovir or valganciclovir: 2-deoxyguanosine analogue, inhibits viral DNA polymerase

foscarnet: analog of pyrophosphate, inhibits pyrophosphate binding site on viral DNA polymerase
cidofovir: 2-doxycytidine analogue, inhibits viral DNA polymerase

CMV doesn’t have a thymidine kinase (acyclovir not effec.)

anti CMV IgG

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symptoms of perinatal infections for CMV

usually none

what is the worst scneario for congenital CMV?

infection during first trimester

symptoms of CMV infection at birth

petechial lesions small size at birth hepatosplenomegaly jaundice

diagnosis of congenital infection

detect in amniotic fluid (or newborn's urine, saliva)

treatment of newborns with CMV

candidate for ganciclovir treatment evaluate for hearing loss, retinitis, neuro fxn

CMV infec in immunosuppressed-what to do

monitor with PCR or IgG | manage with antivirals

another term for human herpesvirus 6b

roseola infantum

what is special of human herpesvirus 6b

its genome can integrate into the host's

prevalance of herpesvirus 6b

90% of kids older than 2 are seropositive

symptoms of herpesvirus 6b

high fever, irritable, malaise, lympahdenopathy

when does human herpesvirus 6b reactivate?

in stem cell transplant recipients

where does human herpesvirus 6b replicate

CD4+ T cells, unknown latency site

treatments for human herpesvirus 6b

no specific, but can use anti-CMV drugs

prevalance of Epstein Barr virus

by early 20s, more than 95% seropositive

shedding of Epstein Barr virus has what symptoms?

90% of intermittent shedding has no symptoms

what diseases does epstein barr virus cause

asymptomatic usually in childhood infectious mononucleosis post transplant lymphoproliferative disorder lymphomas (B, T, NK cell)

envelop or not for Epstein Barr virus

enveloped

how many proteins does ebv genome encode

70 proteins incl DNA replication machinery

where does EBV replicate in

B cells or epithelial cells

where is EBV latent in

memory B cells

What is notable about EBV antigens used for serology?

there are lytic and latent viral antigens

how is EBV transmitted

saliva, blood

where does EBV lytic replication occur?

limited to epithelium of pharynx and B cells b/c of restricted receptor expression

What is notable about EBV latency?

there are two types of latency stages: III, and I/II

what happens in latency stage III

viral antigens are made in proliferating B cells

when does infectious mononucleosis occur?

in latency stage III

what occurs in latency stage II/I

viral antigens are made in memory B cells | the I/II stage can lead to Burkitt's, Hodgkin lymphomas, nasopharyngeal carcinoma

what are the diagnostics for mononucleosis?

atypical T or Downey cells | hterophile antibodies made by B cells in latency III

what occurs in latency stage I?

viral genome is tethered to host chromosome

immune response to EBV-final result

never cleared

humoral response in EBV

neutralizing antibodies have no effect on shed virus

EBV diseases

infectious mononucloesis--overactive immune response | B cell immortalization and lack of immune control (PTLD)

prevalance of symptoms for infectious mononucleosis

30% have symptoms

symptoms of infectious mononucleosis EBV

fever, malaise, lymphadenopathy, exudative pharyngitis, splenomegaly hterophile antibodies symptoms b/c of T cell response

Post transplant lymphoproliferative disorder

immunosuppresive therapy activates infection

therapies for PTLD

no antiviral drugs or vaccines for EBV reduce immunosuppression infuse CTL cell lines

diagnosis of EBV

serology (antibody against antigens-lytic or latent?) for mononucleosis: test for heterophile natibodies with RBC agglutination for PTLD--fluorescent hybrdiz to RNA PCR

EBV associated lymphomas

Burkitt's lympoma (jaw and face) Nasopharyngeal epithelial carcinoma B cell lymomas

Kaposi's Sarcoma prevalance in N america

0-5% in N america | more than 50% in parts of Africa

replication of kaposi's sarcoma virus

CD19+ peripheral B cells, endothelial cells, monocytes, kertainocytes, epithlial

Lymphotropic Herpesviruses Flashcards

(64 cards)