Virus Quantitation Flashcards Preview

RUSVM Virology Summer 2017 > Virus Quantitation > Flashcards

Flashcards in Virus Quantitation Deck (21)
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1
Q

Virus Quantification

A

Count the number of viruses in a specific volume to DETERMINE THE VIRUS CONCENTRATION

2
Q

Virus Titer

A

The LOWEST concentration of a virus that still infects cells. Also defined as the NUMBER OF INFECTIOUS UNITS PER mL OF SAMPLE.

3
Q

What are the two types of virus quantification tests?

A

1) Biological

2) Physical

4
Q

Biological virus quantification tests depends on what?

A

Depends on a virus particle to initiate a successful replication cycle.

5
Q

T/F: A Physical virus quantification test DOES NOT depend on any biological activity of the virus particle

A

True

6
Q

List the biological quantification tests

A

1) Plaque assays
2) Pock assays
3) Various endpoint titration methods
4) Transformation assay
5) Quantal assay

7
Q

Monolayer Plaque Assay- Is this a biological or physical virus quantification test?

A

Biological

8
Q

Plaque

A

A circular zone of necrotic cells surrounded by viable cells in a monolayer
(part of Plaque assay - a biological virus quantification test)

9
Q

What does Plaque- forming units/ mL (PFU) measure?

A

Measures the number of virus particles capable of forming plaques per unit volume.

10
Q

If a solution has a PFU ( plaque- forming units) of 1000 pfu/ mL, then every mL of solution contains enough virus to form, how many plaques?

A

1000 plaques

11
Q

Pock

A

Necrotic area on chorioallantoic membrane (CAM) of embryonate egg. (unit: Pock-forming unit/ mL)
(part of Pock assay - a biological virus quantification test)

12
Q

Transformation assay

A

A biological quantification test that quantitatively determines titers of ONCOGENIC VIRUSES!

13
Q

Endpoint

A

Virus dilution that affects 50% of the TEST SUBJECTS.

part of quantal assay - a biological virus quantification test

14
Q

TCID50

A

The tissue culture infectious dose which will infect 50% of the CELL MONOLAYER challenged with the defined inoculum.
(part of quantal assay - a biological virus quantification test)

15
Q

List Physical quantification tests

A

1) Electron microscopic particle counts
2) Hemagglutination
3) Immunological assay, such as ELISA
4) Quantitative PCR assay
5) Flow cytometry

16
Q

Which of the following is NOT a biological virus quantification test?

A. Pock assay
B. ELISA
C. Plaque assay
D. Various endpoint titration methods

A

B. ELISA – This is a physical virus quantification test.

17
Q

Which of the following is(are) physical virus quantification tests?

A. Flow cytometry
B. Hemagglutination
C. ELISA (Immunological assay)
D. Electron Microscopic particle counts 
E. Quantitative PCR assay
F. Pock assay 
G. Answers A. through E. are correct 
H. All of the above are correct
A

G. Answers A - E are correct

18
Q

Which physical virus quantification test(s), use(s) direct counting of virus particles in solution?

A
  1. Direct particle counts by TEM (Transmission Electron Microscopy)
  2. Virus Counter 2100
19
Q

Which physical virus quantification test(s), use(s) assessment based on antigen concentration?

A
  1. Hemagglutination

2. Single Radial Immunodiffusion (SRID)

20
Q

Which physical virus quantification test(s), use(s) assessment based on gene expression?

A

Quantitative PCR assays

21
Q

Which virus quantification test is the MOST DIRECT method to determine the concentration of virus particles in a sample?

A

Direct particle counts by TEM (Transmission Electron Microscopy)