Laboratory Analysis Of The | Test Questions & Answers Ch.20

Chapter 20: Laboratory Analysis of the Immune Response

= Correct answer

Multiple Choice

1. Most antigens have how many epitopes?

A. none

B. one

C. two

D. more than two

Difficulty: Easy

ASM Standard: N/A

1. Which best describes monoclonal antibodies?

A. They are produced in living animals only.

B. They are produced in tissue cultures, using B cells extracted from living animals.

C. They are rarely used, so polyclonal antibodies are preferred.

D. They can be produced in either living animals or tissue cultures.

Difficulty: Easy

ASM Standard: N/A

1. A hybridoma is which of the following?

A. a cancerous cell

B. a fusion of a B cell and a T cell
C. a fusion of a normal B cell and a myeloma cell
D. a hybrid of two cancerous cells

Difficulty: Easy

ASM Standard: N/A

1. Which is the correct term for a visible antigen-antibody complex?

A. epitope
B. heavy chain complex

C. hybridoma
D. precipitin

Difficulty: Easy

ASM Standard: N/A

1. Monoclonal antibodies bind to which of the following?

A. a single epitope

B. a single hybridoma

C. multiple epitopes

D. variable numbers of epitopes

Difficulty: Easy

ASM Standard: N/A

1. Double immunodiffusion is also known as which of the following?

A. flocculation assay

B. Ouchterlony assay
C. precipitin ring test

D. radial immunodiffusion assay

Difficulty: Moderate

ASM Standard: N/A

1. Which technique is used to help view tissues, using microscopy?

A. electrophoresis

B. immunostaining

C. lateral flow assays

D. western blotting

Difficulty: Easy

ASM Standard: 32

1. Which technique could be used to rapidly diagnose strep throat or mycoplasma pneumonia by labeling bacteria with fluorescent monoclonal antibodies?

A. brightfield microscopy and ELISA techniques

B. fluorescence microscopy and direct fluorescent antibody techniques
C. immunohistochemistry and immunostaining techniques in varying combinations

D. western blotting with chromogens or fluorogens

Difficulty: Easy

ASM Standard: 32

1. Which of the following describes antiserum?

A. a type of vaccine produced in the laboratory

B. antibodies obtained by exposing blood to an antigen in the lab

C. monoclonal antibodies obtained from the blood of an animal injected with an antigen

D. whole serum containing antibodies obtained from an animal exposed to an antigen

Difficulty: Moderate

ASM Standard: N/A

1. When does an antibody test result in a false positive?

A. An individual tests as though she does not have the antigen even though she does.

B. An individual tests as though she has the antigen even though she does not.

C. Antibodies bind to the antigen too strongly, causing an error in the testing protocol.

D. Variations in antibodies cause them to fail to bind to an antigen that is present.

Difficulty: Moderate

ASM Standard: N/A

1. Test sensitivity is defined as which of the following?

A. the probability that an individual will have a false-positive test result

B. the probability that an individual with an infection will test positive

C. the probability that an individual with an infection will test negative

D. the probability that a test will detect multiple antigens simultaneously

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following most commonly results from exposure to a single antigen?

A. A single antibody is produced that can respond to multiple antigens.

B. A single antibody is produced that is specific to that antigen.

C. Multiple antibodies are produced because antigens usually have multiple epitopes.

D. Multiple antibodies are produced to respond to a single epitope.

Difficulty: Moderate

ASM Standard: N/A

1. When a particular test rarely produces false negatives, it has which of the following?

A. high sensitivity

B. high specificity

C. low sensitivity

D. low utility

Difficulty: Moderate

ASM Standard: N/A

1. Compared with the production of polyclonal antibodies, the production of monoclonal antibodies is which of the following?

A. completed without hybridomas

B. easier and faster
C. less expensive

D. more expensive

Difficulty: Moderate

ASM Standard: N/A

1. Which type of antibody is preferable for western blot tests and why?

A. monoclonal antibodies, because they are more sensitive and produce a clearer signal

B. monoclonal antibodies, because they are more specific and less expensive

C. polyclonal antibodies, because they are able to bind to specific epitopes even though they are more expensive

D. polyclonal antibodies, because they can bind to multiple epitopes, generally produce a stronger signal, and are less expensive

Difficulty: Moderate

ASM Standard: N/A

1. What problem makes it difficult to use humanized monoclonal antibody cocktails to treat pathogens?

A. It is less expensive to use monoclonal antibody cocktails rather than purified monoclonal antibodies.
B. It is too technically difficult to separate out the different monoclonal antibodies.

C. Monoclonal antibodies are not sufficiently strong to target pathogens without being used in high concentrations.

D. Monoclonal antibodies are so specific that they may not target all serovars of a pathogen.

Difficulty: Moderate

ASM Standard: N/A

1. Which technique has been proposed to make less-expensive monoclonal antibodies?

A. They can be humanized so that they are easier to use in humans.

B. They can be produced in complex mixtures rather than in purified versions.

C. They can be produced in genetically engineered plants as plantibodies.

D. They can be produced using RT-PCR techniques.

Difficulty: Moderate

ASM Standard: N/A

1. ZMapp is an experimental drug that appeared to be a promising treatment during the 2014–2015 Ebola outbreak. Which is a major limitation to using this type of medication?

A. ZMapp consisted of polyclonal antibodies, so it was not sufficiently specific to work effectively.

B. ZMapp consisted of three monoclonal antibodies to treat multiple Ebola strains, making it prohibitively expensive even if available in sufficient quantities.

C. ZMapp was produced by genetically engineered plants and the virus used to introduce it into plants could cause a problematic immune response in humans.

D. ZMapp was produced in tissue cultures, which is a slow and laborious process that can’t be used to make medications in bulk quantities.

Difficulty: Moderate

ASM Standard: N/A

1. Which of the following correctly describes the effect of a particular factor of a precipitin reaction on the amount of precipitin formed?

A. A 1:1 ratio of antibody to antigen yields the maximum amount of precipitate.

B. Monoclonal antibodies generally bind more and, therefore, produce more precipitate than polyclonal antibodies.

C. The greater the affinity of the antibody for the antigen, the greater the amount of precipitate.

D. The lack of a lattice increases precipitation compared with the presence of a lattice.

Difficulty: Moderate

ASM Standard: N/A

1. The precipitin ring test is used to do which of the following?

A. qualitatively identify the presence of a particular antibody in an antiserum

B. quantify the relative amount of a specific antibody present in an antiserum only

C. quantify the relative amount of a specific antigen present in an antiserum only

D. quantify the relative amounts of a specific antibody and the antigen to which it binds present in an antiserum

Difficulty: Moderate

ASM Standard: N/A

1. Which is the formal definition of an antibody titer?

A. It is a fractional expression of the highest dilution of serially diluted antibody that results in visible precipitation.

B. It is a whole-number expression of the reciprocal of the highest dilution of serially diluted antibody that results in visible precipitation.

C. It represents the highest dilution in a serial dilution test that shows a positive result, rounded to a whole number.

D. It represents the total number of dilutions needed to get a positive result.

Difficulty: Moderate

ASM Standard: N/A

1. What is a major difference between the precipitin reaction test and flocculation assays?

A. Only flocculation involves a visible lattice of antibody and antigen.

B. Only flocculation involves the observation of lipids foaming in a positive result.

C. Only flocculation involves the observation of precipitate in a positive result.

D. Only flocculation involves the use of a serial dilution technique.

Difficulty: Moderate

ASM Standard: N/A

1. A plaque reduction assay is used to quantify which of the following?

A. antibodies produced by a patient during a bacterial infection

B. antibodies produced by a patient during a viral infection

C. antigens produced by a bacterium during a bacterial infection

D. antigens produced by a virus during viral infection

Difficulty: Moderate

ASM Standard: N/A

1. Which test would be most helpful in further examining abnormal patterns of protein abundance previously identified using a PAGE assay?

A. a neutralization assay

B. a precipitin ring test

C. an indirect ELISA test

D. immunoelectrophoresis

Difficulty: Moderate

ASM Standard: N/A

1. Glycerol is used during the precipitin ring test to do which of the following?

A. form a seal to prevent evaporation of the antiserum and antigen

B. fully dissolve the antiserum and antigen into a homogenous solution

C. prevent the antiserum and antigen solutions from mixing at all

D. prevent the antiserum and antigen solutions from mixing except at their interface

Difficulty: Difficult

ASM Standard: N/A

1. Why is cross-matching needed before a blood transfusion?

A. Cross-matching is a final check before transfusion that involves mixing the patient’s blood with a small sample of the blood to be transfused as an additional check.

B. Cross-matching is the first attempt to make sure the blood is compatible before more thorough testing.

C. Cross-matching refers to checking the needed blood type and the blood type of the patient before ordering blood for transfusion.

D. Cross-matching would be needed for planned surgery but is a quality control measure not necessary in an emergency situation.

Difficulty: Difficult

ASM Standard: N/A

1. What causes jaundice and how would the presence of maternal antibodies affect newborn jaundice?

A. Jaundice is caused by excessive breakdown of blood cells; the maternal antibodies activate complement and begin this process.

B. Jaundice is caused by excessive quantities of red blood cells, so having maternal antibodies to the newborn’s cells would reduce the risk of jaundice.

C. Jaundice is caused by the breakdown of blood cells; maternal antibodies inhibit complement production and the newborn’s blood cells, therefore, are vulnerable to destruction.

D. Jaundice is caused by the breakdown of blood cells; maternal antibodies inhibit this process and reduce the risk of jaundice.

Difficulty: Difficult

ASM Standard: N/A

1. Why is a direct hemagglutination assay helpful in detecting the influenza virus?

A. A human cell infected by the influenza virus produces a protein called neuraminidase on its surface that can cross-link red blood cells.

B. The influenza virus has a protein called hemagglutinin on its capsid that can cross-link red blood cells.

C. The influenza virus has a protein called neuraminidase on its surface that can cross-link red blood cells.

D. The influenza virus has multiple proteins on its capsids (hemagglutinin and neuraminidase) that can cross-link red blood cells.

Difficulty: Difficult

ASM Standard: N/A

1. Which test can be used to determine titers of antiviral antibodies in a patient’s serum?

A. the Coombs’ test

B. the cross-matching test

C. the direct hemagglutination assay

D. the viral hemagglutination inhibition assay

Difficulty: Difficult

ASM Standard: N/A

1. Which of the following is not used as a mechanism to detect the presence of antigen in a sample in EIA protocols?

A. When the antigen binds to the antibody, antibody with a bound enzyme will cleave a colorless fluorogen that fluoresces.

B. When the antigen binds to the antibody, antibody with bound alkaline phosphatase will cleave a colorless substrate, releasing a colored product.

C. When the antigen binds to the antibody, antibody with bound horseradish peroxidase will cleave a colorless substrate, leaving a colored product.

D. When the antigen binds to the antibody, the antigen-antibody complex will precipitate, forming an easily observable line at the interface.

Difficulty: Difficult

ASM Standard: 32

1. If you performed a direct ELISA but failed to add the chromogen, which of the following would happen?

A. The antibody would be less visible in the wells if present.

B. The antibody would be unable to bind to the antigen.

C. The antibody would detach from the enzyme.

D. The antibody would not be visible even if present.

Difficulty: Difficult

ASM Standard: N/A

1. Why would a spectrophotometer be helpful in interpreting the results of a sandwich ELISA?

A. It would allow for visualization of the antibody-antigen complex.

B. It would allow one to use a single test to differentiate previous exposure from acute infection.
C. It would be faster, although less sensitive.

D. It would provide more information because the absorbance measured would be proportional to the amount of antigen in the wells.

Difficulty: Difficult

ASM Standard: N/A

True/False

1. The production time for monoclonal antibodies is much faster than the production time for polyclonal antibodies.

Difficulty: Easy

ASM Standard: N/A

1. Lateral flow tests are inexpensive and easy to perform, which has enabled the development of a wide range of diagnostic tests for home use based upon this technology.

Difficulty: Easy

ASM Standard: N/A

1. In direct ELISA testing, a patient’s sample is added to a well with immobilized antibodies already present in its base.

Difficulty: Moderate

ASM Standard: N/A

1. A positive indirect ELISA test is sufficient to make an HIV diagnosis.

Difficulty: Moderate

ASM Standard: N/A

1. CD8 cells can be detected in host tissue by using immunostaining.

Difficulty: Moderate

ASM Standard: N/A

1. A typical home pregnancy test is a lateral flow test that detects human chorionic gonadotrophin in urine.

Difficulty: Moderate

ASM Standard: N/A

1. Seroconversion occurs relatively quickly once someone is exposed to HIV, so detection of antibodies against HIV is recommended using ELISA within a week after exposure.

Difficulty: Difficult

ASM Standard: N/A

1. One test involved in diagnosing systemic lupus erythematosus involves detecting antinuclear antibodies by using indirect fluorescent antibody detection.

Difficulty: Difficult

ASM Standard: N/A

Matching

1. Match each type of assay with an important application of its use.

Answers: A. iv., B. i., C. ii., D. iii.

Difficulty: Moderate

ASM Standard: N/A

1. Match each type of immunoblot or enzyme immunoassay with the best description.

Answers: A. iii., B. i., C. iv., D. ii.

Difficulty: Moderate

ASM Standard: N/A

1. Match each type of assay with a specific procedure that exemplifies it.

Answers: A. i., B. iv., C. iii., D. ii.

Difficulty: Easy

ASM Standard: N/A

1. Match each fluorescent antibody technique with its best description.

Answers: A. ii., B. iv., C. iii. D. i.

Difficulty: Difficult

ASM Standard: N/A

Fill in the Blank

1. PAGE is the abbreviation for ________.

Difficulty: Easy

ASM Standard: N/A

1. Often used to identify a molecule of interest, a(n) ________ is a molecule that can be made to fluoresce.

Difficulty: Easy

ASM Standard: N/A

1. The product of the fusion of a cancerous B cell (a myeloma cell) with a normal B cell is called a(n) ________.

Difficulty: Moderate

ASM Standard: N/A

1. Manufactured antibodies designed to bind to a single epitope are called ________.

Difficulty: Moderate

ASM Standard: N/A

1. The test used to identify proteins after protein gel electrophoresis is called the ________ test.

Difficulty: Moderate

ASM Standard: N/A

1. After ________, the antibody levels in a patient’s serum are high enough for detection, enabling diagnosis.

Difficulty: Moderate

ASM Standard: N/A

1. Lattice formation is detected using the ________ ring test.

Difficulty: Moderate

ASM Standard: N/A

1. Flocculants are formed by ________ antigens in a suspension.

Difficulty: Moderate

ASM Standard:

1. Plates that allow multiple reactions to be run side by side in a small area, such as those used in ELISA testing, are called ________ plates.

Difficulty: Moderate

ASM Standard: N/A

1. Because antibodies can cause bacterial serovars to clump, ________ assays based on this characteristic can be used to identify the serovars.

Difficulty: Difficult

ASM Standard: N/A

1. Herceptin is an example of a(n) ________ that can be used to treat cancer.

Difficulty: Difficult

ASM Standard: N/A

Short Answer

1. Why is a chromogen used in ELISA testing?

Sample

Difficulty: Easy

ASM Standard: N/A

1. If you do a neutralization assay and find there are antibodies to a virus, does that mean the patient has a current infection with that virus? Why or why not?

Sample

Difficulty: Easy

ASM Standard: N/A

1. What is flocculation?

Sample

Difficulty: Easy

ASM Standard: N/A

1. What does ELISA stand for?

Sample

Difficulty: Easy

ASM Standard: N/A

1. Why is a chromogenic substrate sometimes used in western blotting?

Sample

Difficulty: Easy

ASM Standard: N/A

1. How do direct and indirect ELISA differ?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. What is a disadvantage of using monoclonal antibodies to detect bacterial serovars?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. You want to test whether a patient has a current viral infection. You conduct a first neutralization assay and then conduct a second assay after 2 weeks. You find that a one-fourth dilution is the greatest dilution that produces a 50% plaque reduction for the first assay. For the second assay, you find that a 1/32 dilution is the greatest dilution that produces a 50% plaque reduction. What were the patient’s titers for the first and second tests? Does the patient have a current infection?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. How is IEP useful in diagnosing multiple myeloma?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. How does southwestern blotting differ from western blotting?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. What is the purpose of the complement fixation test?

Sample

Difficulty: Moderate

ASM Standard: N/A

1. Why are red blood cells especially useful for evaluating complement-mediated cytolysis and for the complement-fixation test?

Sample

Difficulty: Difficult

ASM Standard: N/A

1. During the complement fixation test, why is it necessary to heat patients’ samples?

Sample

Difficulty: Difficult

ASM Standard: N/A

1. Give an example of a clinical test that uses flocculation.

Sample

Difficulty: Difficult

ASM Standard: N/A

1. How would your results be affected if you did an indirect ELISA test and did not sufficiently rinse the patient serum from the plates before adding the secondary antibody-enzyme complex? Why would this occur?

Sample

Difficulty: Difficult

ASM Standard: N/A

Brief Essay

Essay Question Rubric

Assume rating/grading scale for the question ranges from 0 to 3 points.

1. Explain the process used to produce polyclonal antibodies.

Difficulty: Moderate

ASM Standard: N/A

1. Why would it be a problem to inject monoclonal antibodies from mouse cells directly into humans? How is this problem addressed?

Difficulty: Moderate

ASM Standard: N/A

1. Explain the trade-offs involved in evaluating sensitivity and specificity in choosing a test for the detection of HIV. In your answer, reference the types of HIV tests currently used.

Difficulty: Difficult

ASM Standard: 31a

1. New testing approaches will make it easier for people to test for diseases such as HIV at home, as with a home pregnancy test. Discuss the pros and cons of the increased use of direct-to-consumer sales of tests for such serious illnesses. Include an overview of some of the types of tests that are facilitating this trend.

Difficulty: Difficult

ASM Standard: 31

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