Herpes Flashcards
alpha herpes virus
HSV, VZV
beta herpes virus
CMV, HHV6, 7
gamma herpes virus
EBV
How can lytic herpes lytic replication result in transmisison?
Active disease or
Asymptomatic shedding
Lytic replication in permissive cells is ______
cytopathic = kills cells –> disease
Small subset of viral genes expressed but NO infxous particles are produced
latency
*reactivation of latent infxn is source of majority of symptomatic disease
ALpha:
Establish latent infxn in _____ of PNS , primarily in _____ nerve ganglia
neurons of PNS
sensory
Beta:
establish latent infxns in _____ lineage and ____ cells
myeloid and endothelial cells
gamma:
establish latency in ____ cells, capable of transforming these cells, which are important bc:
B cells,
endothelial cells
transforming cells: capable of giving rise to cancer
Herpes lytic replication cycle
translation:
- Immediate early: transcribed soon after virus entry
- set up conductive environment for viral rep to occur
- needed for subseq expression of E and L genes - Early
- encode replication enzymes and non structural proteins - Late
expression
- encode viral proteins needed for assembly and egress (get out of cell)
Viral glycoproteins mediate ____. Are targets of _____.
- cellular tropism
2. targets of adaptive immune response
Which if the herpes virus are spread by respiratory secretions?
VZV
Big herpes virus to worry about with transplants
CMV
genome replication rolling circle replication
- Nick on 1 strand
- 5’–>3’ : template for replication
“rolling circle replication”
tx for alpha viruses and beta viruses
A: acyclovir
- uses viral thymidine kinase to make drug active *phosphorylated
A+B: gancyclovir
- beta viruses do not have viral TK so acyclovir wont work
- gancyclovir makes a kinase able to do first phosphorylation step
Cidofovir
*cidofovir and foscarnet work downstream of phosphorylation: more side effects
Foscarnet
*cidofovir and foscarnet work downstream of phosphorylation: more side effects
Intranuclear capsidation
scaffold proteins transported in form cytoplasm
- procapsid Assembly around scaffold protein
- Becomes mature capsid
- DNA with cleavage/packaging proteins stored in mature capside –> encapsidation
*see image
Intranuclear histology:
acidophilic
basophilic
- Acidophilic:
Cowdry type A
- (HSV, VZV) - Basophilic:
Owl eyes
- (CMV)
Innate and adaptive immune response to herpes virus
- Innate immune response
- IFN/cytokine production
- NK cell activities - Adaptive immune response
- neutralizing antibodies
- CD4+ and CD8+ T cell fxn
*herpes virus can counter each of these
Papules are formed from:
Vesicles are formed from:
Cells at/above basal layer are infected and lyse –> inflammatory response –>
Papule
Lysis of cells with resultant cytokines –> inflammation –> fluid production –>
Vesicle
Which HSV is above the belt and which below the belt?
Type I: above belt
Type II: below the belt
- unless its oral-genital contact
Typical skin lesions of VZV occurs when?
when immune response develops
- 10-21 days
Varicella ascends in ______ nerves from the skin and remains in _____ ganglia for life
sensory nerves
sensory ganglia
