viruses

Question 1

TLRs for Viruses

Answer 1

3 for dsdna in endosome leads to IFN B

7 for ssRNA leads to IFN a and b

Question 2

Innate response to viruses

Answer 2

Infected cells produce IFN a and b, IL6, IL12, chemokines

1. self to increase IFN exp
2. paracrine - alert cells to virus state and increase DAI a transL inhib
3. Increases MHC exp for CTL NK and DC recog

Question 3

Adaptive response to viruses

Answer 3

Recruit TH1 via MHC 1 to resolve

Recruit TH2 to make antiviral Abs

Question 4

Timeframe of virus

Answer 4

Acute - influenze Latent - chickenpox

Question 5

Viral evasion strategies

Answer 5

1. Ag variation
2. downreg mhc 1
3. downreg LFA3 and Icam
4. Infect immunopriveledged sites
5. Infect immune system

Question 6

Helical enveloped viruses

Answer 6

Paromyxovirus, Rabies - dev protomer with nuc acid with each polypeptide

Question 7

Icosahedral viruses

Answer 7

Adenovirus; can be empty

Question 8

Enveloped virus

Answer 8

HIV; peplomers on envelope

Question 9

Complex virus

Answer 9

doub membrane; smallpox

Question 10

Stages of viral infection

Answer 10

attach, penetrate, uncoat, macromolec synth and rep, assembly, progent

Question 11

Penetration stage of infection

Answer 11

1. Surface fusion - ph indep, membrane fusion leading to syncytia ex: pesvirus, paramyxovirus, HIV
2. Endosomal fusion (enveloped viruses) - ph dep via receptor to endosome to nuc, influenze
3. Lysosomal uncoat - adenovirus, binds r, naked to endosome, release in cytoplasm, nucleoplasmid with coat binds nuc envelope and injects
4. Pore formation - poliovirus, virus docks, endo, and releases nuc from endosome via pore

Question 12

HIV binding

Answer 12

gp120CD4, CCR5, gp41 penetration, membrane fusion

Question 13

Replication sites

Answer 13

1. Cytoplasm: most RNA viruses (except = Retrovirus) and Poxvirus (DNA)
2. Nucleus: most DNA viruses (except = Poxvirus) and Orthomyxovirus (RNA)
   1 and 2: Retrovirus and Hep (DNA virus)

Question 14

dsDNA rep

Answer 14

Herpes, papillomavirus - uses host DNA and RNA poly (ex = poxvirus brings own DNA and RNA poly

Question 15

ssDNA

Answer 15

Parovirus - uses host DNA and RNA poly

Question 16

dsDNA

Answer 16

Rotavirus - makes own RNA transcriptase and RNA replicase

Question 17

ssRNA + sense

Answer 17

+ taken by ribosome to polyproteins (degraded to form functional units) to make viral RNA poly to transC - RNA and viral RNA poly to rep (ex = Poliovirus, Rhinovirus, Flavivirus)

Question 18

ss - sense RNA

Answer 18

Influenza Measles - packed with RNA polymerase, use RF as needs + to rep, synth of proteins via polycistronic and segmented genome

Question 19

ss + sense RNA with DNA intermediate

Answer 19

Retrovirus and HIV, Has viral reverse transcriptase to make RNA/DNA hybrid to dsDNA and uses host RNA poly

Question 20

partially dsDNA w/RNA intermediate

Answer 20

HepB; moves to nuc as circ DNA, uses host RNA poly to make - sense strand, brings reverse transcriptase with DNA poly

Question 21

Segmented Genome

Answer 21

allows genomic mixing, reassortment ie 2 variants infect cell and create noval virus

Question 22

Phenotypic mixing

Answer 22

2 diff viruses same cell - change coat and therefore tropism

Question 23

Diag inclusion bodies

Answer 23

Negri bodies - Rabies; Owl Eyes - CMV

Question 24

HAI Assay

Answer 24

Hemagglutination inhib for antiviral titer so dot = virus

Question 25

Hemadsorption

Answer 25

RBC binds to viral peplomers expressed by inf cells
Measles: syn and hemad
RSV: syn
Flu: hemad