Virology

Question 1

Cytopathic effect

Answer 1

Cells infected with most viruses eventually show this effect
Shrinkage of cell nucleus
Development of inclusion bodies
Cell rounding
Detachment of cells (eventually)

Question 2

Negri bodies

Answer 2

Inclusion body in infected neurons

Rabies virus

Question 3

Owl eye cells

Answer 3

Cell swells and nucleus becomes pyknotic --> dense center surrounded by clear halo
Human cytomegalovirus (HCMV)

Question 4

Transformed cell

Answer 4

Immortalized cells that has also accumulated mutations that give it properties beyond continued cell division; lose contact inhibition –> can pile on top of each other
Models for studying cancer

Question 5

factors influencing severity and resistance to viral infections

Answer 5

1. innate defenses
   - -skin: layer of dead cells, skin secretions, normal bacterial flora
   - -mucosal tissues: mucous w/ sialic acid, defensins (**beta and cathelecidins, AMPS), lactoferrin, saliva, cilia
   - -GI: low pH, proteases, bile salts, lipases, mucosal layer, peristalsis, AMPS
2. age
3. hormones: corticosteroids, preg hormones
4. nutrition
5. fever: due to IFN alpha, IFN beta, IL-1beta

Question 6

RIG-1 (retinoids acid inducible gene- 1)

Answer 6

binds non-capped RNA and small RNAs encoded by Epstein Barr

detect picornaviruses

Question 7

MDA 5 (melanoma differentiation associated gene 5)

Answer 7

detects double stranded RNA (common replication intermediate)
signaling occurs through a cellular body called IPS-1 signalosome

Question 8

TLRs that are intracellular

Answer 8

TLR 3, 7, 8, 9
involved in recognizing viral infections
activated by nucleic acid structures specific to virally infected cells

Question 9

APOBEC

Answer 9

family of proteins that inhibit HIV
dominate cytokines in the first strand of DNA of HIV causing mutations and degradation of the genome prior to integration
packaged in virus particles and then act when the virus enters a new host cell

Question 10

TRIM4alpha

Answer 10

inhibitor of HIV
protein that binds to the HIV capsid and accelerates uncaring which inhibits reverse transcription
also traffics viral capsids to proteosomes where they are digested

Question 11

tetherin

Answer 11

inhibitor of HIV

located in the plasma membrane and prevents the release of virions from the cell

Question 12

PKR (protein kinase R)

Answer 12

IFN induced protein
antiviral effector
phosphorylates eukaryotic initiation factor 2A –> halts the initiation of protein synthesis
activated by double stranded RNA which is present in large amounts in a virus infected cell

Question 13

herpes virus alpha, beta, and gamma groups

Answer 13

based on biological properties and sequence homologies

alpha: neurotrophic viruses, HSV-1, HSV-2, VZV
beta: HCMV, HHV-6A, HHV-6B, HHV-7
gamma: EBV, HHV-8

Question 14

herpes reactivation triggers (5)

Answer 14

fever
stress
nerve trauma
changes in steroid hormones
UV light

Question 15

sylvan cycles

Answer 15

virus is maintained in wild with transmission occurring between some animal and insect vectors
often causes asym infection in endemic host but is lethal for some other species

Question 16

maintenance of vector transmitted viruses in nature (3)

Answer 16

hibernating small animals
transovarial transmission in arthropods
asym animal hosts w/ chronic infection