Unit 4 General

Question 1

antigenic drift

Answer 1

Gradual change in amino acid sequence of flu on H or N surface antigens.

Question 2

antigenic shift

Answer 2

Occurs in A type flu only. Occurs when novel H or N gene segment is introduced to humans.

Question 3

Pandemic Criteria

Answer 3

• emergence of new flu subtype
• virus must infect humans and cause serious illness
• virus must have sustained human to human transmission and spread easily among humans

Question 4

positive sense RNA virus

Answer 4

can be directly translated

Question 5

negative sense RNA virus

Answer 5

requires RNA-dependent RNA polymerase for replication

Question 6

dsRNA virus

Answer 6

requires RNA-dependent RNA polymerase for replication

Question 7

plaque assays

Answer 7

measure infectivity of a sample

Question 8

reverse transcriptase is required for what type of virus?

Answer 8

+ ssRNA virus with DNA intermediate

Question 9

latent viral infection

Answer 9

initial infection followed by asymptomatic periods with occasional reactivation

Question 10

cytotoxic T cells

Answer 10

• adaptive immune defense
• associated with killing virally infected cells
• CD8+

Question 11

dsDNA virus

Answer 11

-conventional transcription and translation

Question 12

gapped circular dsDNA

Answer 12

• translated into regular dsDNA, then to RNA then to protein
• RNA is reverse transcribed to make DNA for next virus?
• hepatitis B virus

Question 13

ssDNA

Answer 13

• made to dsDNA
• transcribed to RNA and madd to protein
• also replicated into DNA for next virus

Question 14

dsRNA

Answer 14

• encodes RNA dependent RNA polymerse (RdRp)

- can be translated into protein

Question 15

ss(+)RNA

Answer 15

• translated directly into protein
• encodes RNA dependent RNA polymerase (RdRp)
• ex. SARS, yellow fever, hep C, HIV

Question 16

ss(-)RNA

Answer 16

• encodes RNA dependent RNA polymerase (RdRp)
• NOT translated directly to protein
• translated into +RNA then into protein

Question 17

ss(+)RNA with DNA intermediate

Answer 17

• +ssRNA is never used as a message
• ssRNA is converted to dsDNA with reverse transcriptase
• dsDNA intermediate integrates into host genome and is permanent (provirus)

Question 18

Innate TLRs involved in antiviral response

Answer 18

TLR3 (dsRNA), TLR7 (viral RNAs, synthetic ligands), TLR9 (unmethylated CpG)

Question 19

innate intracellcular restriction factor antiviral responses

Answer 19

• APOBEC
• TRIM5
• TLRs (3, 7, 9)
• helicases

Question 20

innate anti-viral defense cells

Answer 20

• mononuclear phagocytes
• dendritic cells
• NK cells
• granulocytes

Question 21

innate antiviral cytokines

Answer 21

-IFNs, IL1, TFNa, IL6, IL12, IL18

Question 22

innate antiviral chemokines

Answer 22

• IL8, IP10, MIP1a

- chemical that will attract other cells

Question 23

Innate Defense Mechanisms

Answer 23

• barriers
• intracellular restriction factors
• interferons
• anti-viral cells
• cytokines
• chemokines

Question 24

innate interferons

Answer 24

-IFNs (type 1, type 2, jakstat, PKR (dec. protein synth), OAS (degrade mRNA))

Question 25

adaptive antiviral cells

Answer 25

• B cells
• T cells
• macrophages
• hepatocytes

Question 26

tissue tropism

Answer 26

-certain viruses prefer certain tissues over other

Question 27

virulence

Answer 27

-ability of infection to cause disease

4 Types

• affect ability of virus to replicate
• modify host defense mechanisms
• facilitate virus spread
• directly toxic to host cells

Question 28

acute local viral response

Answer 28

• short incubation times (1-3 days)
• IgA
• cold and diarrhea
• epithelial infection
• high likelihood of reinfection

Question 29

acute systemic viral response

Answer 29

• longer incubation time (10-20 days)
• IgA and IgG
• low likelihood of reinfection

Question 30

latent viruses

Answer 30

• HSV- dorsal root ganglia
• HPV-basal epithelial cells
• EBV-B lymphocytes
• VZV
• virus for MS?