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MIIM30014 Virology > Vectors and Vaccines (21,22) > Flashcards

Vectors and Vaccines (21,22) Flashcards

1
Q

What is involved in transfecting poliovirus RNA into cultured cells?

a. cDNA is cloned into a plasmid with a RNA pol II promoter
b. In vitro RNA synthesis requires cellular RNA pol
c. cDNA is directly transfected into cultured cells
d. Poliovirus cannot directly infect cultured cells

A

a. cDNA is cloned into a plasmid with a RNA pol II promoter

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2
Q

A requirement of a viral vector is:

a. Must not be replicative defective
b. Must have the capacity to produce and release new infectious particles
c. The sequences for replication and particle production must not be separated
d. The transgene must be flanked by essential cis-acting sequences and packing signals

A

d. The transgene must be flanked by essential cis-acting sequences and packing signals

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3
Q

Which viral vector can not be used on non-dividing cells?

a. Adenovirus
b. AAV
c. Lentivirus
d. Retrovirus

A

d. Retrovirus

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4
Q

Which statement is correct?

a. Adenovirus vectors have a lower titre than Adeno-associated vectors
b. Adeno-associated vectors can only carry a small insert of about 4.5kb
c. Retrovirus and Herpes virus can infect non-dividing cells
d. Adenovirus, Lentivirus and Retrovirus show poor tropism

A

b. Adeno-associated vectors can only carry a small insert of about 4.5kb

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5
Q

What is true about retro and lentiviral vectors?

a. Both have an insert size of 9.2kb
b. The LTR and packing signal are retained from both viruses
c. Tat is retained and pol is deleted from both viruses
d. Retroviruses are larger vectors than lentiviruses

A

b. The LTR and packing signal are retained from both viruses

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6
Q

How can the LTR be modified to preserve reverse transcriptase activity and integration but stop LTR transcription?

a. By duplicating the U3 and U5 sequences in the LTR
b. By silencing att sites found in the vector plasmid
c. By deleting the U3 sequence in the LTR and allowing the expression of a heterologous promoter
d. By silencing all heterologous promoters found in the vector plasmid

A

c. By deleting the U3 sequence in the LTR and allowing the expression of a heterologous promoter

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7
Q

What is an issue with retroviral vectors and how is it avoided?

a. A replication competent virus may be regenerated so this is prevented by activating LTR expression
b. Heteroglous gene expression grows over time so this is down-regulated using Tat expression
c. Viral transcriptional elements can have biosafety concerns so this is prevented by removing Tat
d. Structural proteins can only be expressed from the same plasmid and this is aided through the use of packing cells with endogenous retrovirus

A

c. Viral transcriptional elements can have biosafety concerns so this is prevented by removing Tat

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8
Q

What is a feature of an application of retro or lenti viral vectors?

a. They can be used in cancer therapy and are expressed transiently and at high levels
b. They can be used in vaccine development and activate the immune response, but expression levels are low
c. They can be used in gene therapy without any risks of insertional mutagenesis
d. They are inefficient in vaccine development as they only activate an innate immune response

A

a. They can be used in cancer therapy and are expressed transiently and at high levels

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9
Q

What part of the viral genome needs to be retained when constirctuing an adenoviral vector?

a. The LTR and E1 protein
b. The ITR and packing signal
c. At least one LTR and an ITR
d. E1, E3 and E4

A

b. The ITR and packing signal

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10
Q

What is false about adenovirus expression vectors?

a. They can efficiently transduce mammalian cells and grow to high titres
b. Heterologous genes are cloned in place of E1, E3 and E4
c. They do not elicit a T cell response and are therefore expressed for a long time
d. Pre-existing immunity in about 40% of people can reduce efficiency

A

c. They do not elicit a T cell response and are therefore expressed for a long time

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11
Q

What is a feature of the gutless adenovirus expression vector?

a. Cre-recombinase inserts heterologous genes into the ITR
b. LoxP sites are recognised by cre-recombinase to excise adenovirus genes
c. The insert sizes are smaller than normal adenovirus vectors due to the removal of immunogenic genes
d. It can only be used in dividing cells

A

b. LoxP sites are recognised by cre-recombinase to excise adenovirus genes

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12
Q

What is not a feature of AAV vectors?

a. They are developed from viruses of the adenoviridae family
b. They infect dividing and non-dividing cell
c. They require a cell line with helper proteins to assist packaging
d. They often integrate into DNA on chromosome 19

A

a. They are developed from viruses of the adenoviridae family

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13
Q

Which viruses can be used as +ssRNA vecotrs?

a. Herpesvirus and adenovirus
b. Calicivirus and Reovirus
c. Flavivirus and alphavirus
d. Togavirus and Bunyavirus

A

c. Flavivirus and alphavirus

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14
Q

What is a feature of RNA replicons?

a. Replication is host cell dependent
b. Replication occurs in the nucleus
c. They can only be delivered as VLPs
d. They lead to high expression of heterologous genes

A

d. They lead to high expression of heterologous genes

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15
Q

What is false about WNV strain Kunjin replicons?

a. They express high levels of heterologous genes in the cytoplasm
b. VLPS are produced following transfection into a packing cell line expressing structural genes
c. The vectors integrate and recombine with the host genome and are therefore noncytopathic
d. The dsRNA intermediate elicits an enhanced immune response that can benefit vaccine development

A

c. The vectors integrate and recombine with the host genome and are therefore noncytopathic

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16
Q

• DNA virus promoters can drive a high level of gene expression.

A

T

17
Q

• All retroviruses integrate a provirus into the genome and can only infect non-dividing cells.

A

F

18
Q

• Nearly all of the genes in herpes virus are essential for function and herpes virus vectors can therefore only have small inserts.

A

F

19
Q

• The VSV virus expression system can express ebola glycoproteins to act as a potential ebola vaccine.

A

T

20
Q

A vaccine should:

a. Prime the innate immune response
b. Lead to a primary response when a vaccinee is infected with the pathogen
c. Be safe, effective and stable
d. Cause disease and immunity in the host

A

c. Be safe, effective and stable

21
Q

When does the initial adaptive immune response occur?

a. Within hours of exposure
b. Between 7 and 14 days after exposure
c. 35 days after exposure
d. 21-28 days after exposure

A

b. Between 7 and 14 days after exposure

22
Q

Which vaccine is not produced via a cloning step?

a. DNA vaccine
b. Live Virus vector
c. Virus like particles
d. Non-recombinant purified subunit vaccine

A

d. Non-recombinant purified subunit vaccine

23
Q

Which statement about the history of smallpox vaccine is true?

a. Post Jenner methods used vaccinia
b. Jenner used attenuated human small pox
c. Pre-jenner methods were most successful due to the discovery of viruses in 1892
d. Post Jenner methods involved taking material from smallpox pustles and putting it in a scratch on the arm

A

a. Post Jenner methods used vaccinia

24
Q

What aided in the eradication of smallpox?

a. The virus has a short incubation period
b. The virus had one stable serotype
c. Small pox infection was persistent
d. The infection resulted in short term immunity

A

b. The virus had one stable serotype

25
Q

What is a feature of the poliovirus vaccines?

a. The IPV vaccine was created from 3 different attenuated strains of the virus
b. The OPV vaccine is extremely neurovirulent
c. The Sabin vaccine showed higher levels of nasal and duodenal IgA
d. The OPV vaccine was made after being inactivated with formalin

A

c. The Sabin vaccine showed higher levels of nasal and duodenal IgA

26
Q

What is true about the attenuated strains used to create the Sabin poliovirus vaccine?

a. Strain type 2 was only mutated at the 3’ UTR
b. All strains were mutated at the 5’UTR and in some VP genes
c. Type 1 and 2 have a risk of reverting
d. 1 in 20 vaccinated individuals develop paralysis

A

b. All strains were mutated at the 5’UTR and in some VP genes

27
Q

What happens in SSPE?

a. A measles virus has a mutation that allows persistent survival and brain inflammation
b. A smallpox virus fails to produce infectious particles and survives persistently
c. A measles virus has a mutation that allows up-regulation of structural genes
d. A poliovirus re-assorts and becomes neurovirulent

A

a. A measles virus has a mutation that allows persistent survival and brain inflammation

28
Q

What is a feature of live attenuated viral vaccines?

a. They require many doses
b. They are effective against immunocompromised people
c. The virus may be shed into the environment
d. There is no risk of reversion back to virulence

A

. The virus may be shed into the environment

29
Q

What is not a feature of using a vaccinia virus vector?

a. The bacterial plasmid contains part of the vaccinia genome encoding TK and this is disrupted by the insertion of an early gene promoter
b. The antigen can be expressed to high levels and delivered by the mucosal route
c. Due to homologous recombination, the mutated gene segment can be inserted into the vaccine virus
d. It is most effective in immunocompromised individuals

A

d. It is most effective in immunocompromised individuals

30
Q

What is a feature of a DNA vaccine?

a. It cannot be delivered via a gene gun due to discrepancies in polarity
b. The plasmid is amplified and purified in yeast
c. The plasmid contains a bacterial ori, eukaryotic promoter and antibiotic resitance marker
d. DNA vaccines are inefficient when delivered to the dermis

A

c. The plasmid contains a bacterial ori, eukaryotic promoter and antibiotic resitance marker

31
Q

VLP vaccines:

a. Cannot be used to prevent hepatitis B
b. Involve the self-assembly or capsid or envelope proteins
c. Are not very immunogenic
d. Cannot be taken up by antigen presenting cells

A

b. Involve the self-assembly or capsid or envelope proteins

32
Q

What is not a feature of the HPV vaccine?

a. It is a whole attenuated virus vaccine that protects against cervical cancer
b. It causes 99.5% seroconversion
c. It is based on the rec L1 capsid protein which can be expressed in yeast
d. It can aid in wart regression and protection against HPV16

A

a. It is a whole attenuated virus vaccine that protects against cervical cancer

33
Q

What is a feature of live attenuated viral vaccines made by genetic reassortment?

a. They can only be used or viruses with non-segmented genomes
b. The Flumist vaccine uses HA and NA of the current influenza strain and 6 genes from a cold-adapted master strain
c. Both parent viruses must be pathogenic
d. The Flumist vaccine reassortant virus can grow in both the URT and lungs

A

b. The Flumist vaccine uses HA and NA of the current influenza strain and 6 genes from a cold-adapted master strain

34
Q

• An example of a natural passive vaccine is maternal IgG.

A

T

35
Q

• The most successful vaccines are live virus vectors because they can replicate

A

. F (live-attenuated)

36
Q

• Polio is only endemic in Nigeria.

A

F

37
Q

• The poliovirus IPV vaccine is more widely used than the OPV vaccine due to reversion risks.

A

T

38
Q

• Vaccination can reduce the rates of encephalitis from measles and mumps infection.

A

T

39
Q

• HPV 6 and 11 cause cancer and HPV 16 and 18 cause genital warts.

A

F

MIIM30014 Virology (23 decks)

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