Question 1

You wish to determine which cells contain the protein Substance P in the skin surrounding a flesh wound.Skin scrapings are obtained,fixed in formalin,and mounted on slides.You have an anti-Substance P antiserum.What immunochemical protocol would be most appropriate to use for this experiment?

A) ELISA
B) Western blotting
C) Double immunodiffusion
D) Immunocytochemistry

Immunocytochemistry

Accepted Answer

Immunocytochemistry is the most appropriate protocol to use for this experiment. It allows for the visualization of the spatial distribution of Substance P in the cells of interest. ELISA and Western blotting are better suited for measuring the amount of a specific protein in a sample, but not for determining its location in cells or tissues. Double immunodiffusion is an outdated technique and would not be as sensitive or specific as immunocytochemistry.

Question 2

In a noncompetitive immunoassay reaction format,a very high concentration of analyte antigen in the unknown sample might produce a falsely:&#10;A) decreased result because the high concentration of antigen binds both the capture and labeled antibody,reducing the number of complexes formed.&#10;B) increased result because the rate of the forward reaction of antigen-antibody binding is too fast,leading to a high equilibrium constant.&#10;C) decreased result because of the free excess antigen-binding all antibody sites and not allowing any unlabeled antigen to bind.&#10;D) increased result because the second labeled antibody will be able to react with the substrate by itself since excess antigen will interfere with any binding.

Accepted Answer

A very high concentration of analyte antigen can saturate both the capture and labeled antibody, reducing the number of antigen-antibody complexes formed. This can lead to a falsely decreased result in a noncompetitive immunoassay reaction format.

Question 3

In this heterogeneous assay,one of the reaction components is attached to the surface of a solid phase.An aliquot of patient sample containing the analyte of interest is added,a wash step occurs,and an enzyme-labeled antibody different from the bound antibody is added followed by the substrate.This type of assay is called:

A) enzyme-linked immunosorbent assay (ELISA).
B) reflectance immunoassay.
C) enzyme-multiplied immunoassay technique (EMIT).
D) fluorescence polarization immunoassay (FPIA).

Accepted Answer

This description matches the standard protocol for an enzyme-linked immunosorbent assay (ELISA), where one of the reaction components, usually an antibody, is bound to the surface of a solid phase (e.g. a microplate). The patient sample is added, allowing the analyte of interest to bind to the immobilized antibody, which is then detected using a secondary enzyme-labeled antibody and a substrate that produces a measurable signal. Reflectance immunoassay, EMIT and FPIA are different types of immunoassays with distinct characteristics and methodologies.

Question 4

In a precipitin reaction,an excess of antigen over an antibody will lead to:&#10;A) all antigen sites bound with an antibody and no precipitate formation.&#10;B) all antibody sites bound by antigen with no formation of precipitate.&#10;C) cross-linking of antigen and an antibody with maximal precipitate formation.&#10;D) a lack of reaction between an antibody and antigen,and no precipitate.

Accepted Answer

In a precipitin reaction, when there is an excess of antigen, all the antibody binding sites become saturated with antigen molecules, but there may not be enough antibody molecules to cross-link the antigens into a visible precipitate. This results in all antibody sites being bound by antigen but no formation of precipitate because the necessary lattice structure for precipitate formation cannot be formed.

Question 5

In an enzyme immunoassay with an enzyme-labeled antigen,if there is a high concentration of patient antigen,will there be _____ enzyme available to bind substrate.&#10;A) more&#10;B) less

Accepted Answer

If there is a high concentration of patient antigen, there will be more enzyme-labeled antigen available to bind with substrate, resulting in a higher concentration of enzyme-substrate complex and a stronger signal in the assay. Therefore, the best choice is A.

Question 6

A homogeneous fluorescence immunoassay that involves the speed of the rotation of molecules,which is then related to analyte concentration in a patient sample,is known as:&#10;A) ELISA.&#10;B) reflectance immunoassay.&#10;C) enzyme-multiplied immunoassay technique.&#10;D) fluorescence polarization immunoassay.

Accepted Answer

The description given in the question matches the principle of fluorescence polarization immunoassay. In this assay, a fluorescent molecule is tagged to the analyte-specific antibody, and when the sample is excited with polarized light, the rate of rotation of the fluorescent molecule changes based on the presence or absence of analyte. Higher analyte concentration in the sample causes a decrease in fluorescence polarization, which is then measured and correlated with the concentration of analyte. ELISA, reflectance immunoassay, and enzyme-multiplied immunoassay technique use different principles for analyte detection.

Question 7

Which immunoassay uses a label that was susceptible to making serum cause a false positive because of background fluorescence?&#10;A) Enzyme&#10;B) Radioactive&#10;C) Chemiluminescent&#10;D) Fluorescent

Accepted Answer

Fluorescent immunoassays can be susceptible to false positives due to background fluorescence present in the serum. This background fluorescence can interfere with the assay's ability to accurately measure the specific signal, leading to incorrect results.

Question 8

In a noncompetitive immunoassay reaction format:&#10;A) all reactants are mixed together with both the labeled and unlabeled antigens binding to the antibody.&#10;B) an unlabeled antigen is first mixed with excess antibody and binding reaches equilibrium.Labeled antigen is then added.&#10;C) antigen from an unknown sample is allowed to react with a solid-phase antibody,and a second labeled antibody is added that reacts with bound antigen.&#10;D) bound label is inversely proportional to the unlabeled antigen concentration.

Accepted Answer

In a noncompetitive immunoassay, the choice C best describes the format. The assay involves allowing antigen from an unknown sample to react with a solid-phase antibody, followed by the addition of a second labeled antibody that reacts with bound antigen. This format enables the detection of the antigen-antibody complex formed by the unknown sample and the solid-phase antibody, resulting in the measurement of the target antigen. Choice A is incorrect because in this format, both the labeled and unlabeled antigens bind to the antibody, resulting in competition for binding sites. Choice B describes a competitive immunoassay, not a noncompetitive format. Choice D is not a characteristic of a noncompetitive immunoassay.

Question 9

Certain immunoassays require separation of bound reactant from free-labeled reactant for determination of analyte concentration.Which one of the following immunoassays requires this separation step?&#10;A) Fluorescence polarization immunoassay (FPIA)&#10;B) EMIT&#10;C) Cloned enzyme donor immunoassay&#10;D) ELISA

Accepted Answer

ELISA is the only immunoassay listed that requires separation of bound and free reactants for determination of analyte concentration. This is typically done using a washing step to remove unbound labels before measuring the signal. FPIA measures polarization of fluorescently-labeled reactants, EMIT measures the amount of fluorescence emitted by labeled reactants, and Cloned enzyme donor immunoassay measures the activity of an enzyme reporter fused to the analyte-specific antibody. None of these methods require separation of bound and free reactants.

Question 10

An antibody that has very strong affinity to a single antigenic epitope is referred to as a(n)_____ antibody.&#10;A) affinity-purified&#10;B) monoclonal&#10;C) polyclonal&#10;D) multiclonal

Accepted Answer

Monoclonal antibodies are produced from a single type of B cell, resulting in highly specific binding to a single epitope on an antigen. Affinity-purified antibodies are those that have been purified based on their binding affinity, but this does not necessarily imply specificity for a single epitope. Polyclonal antibodies are produced from multiple types of B cells and can bind to multiple epitopes on an antigen. Multiclonal is not a recognized term in the field of immunology.

Question 11

The light-scattering immunochemical method that is considered to have the best sensitivity and a lower detection limit for serum proteins is:&#10;A) nephelometry.&#10;B) electroimmunoassay.&#10;C) turbidimetry.&#10;D) Western blotting.

Accepted Answer

The answer of The light-scattering immunochemical method that is considered...

Question 12

The component of an immunoglobulin molecule that determines the antigenic specificity of that antibody is the:&#10;A) disulfide bond linkage between the heavy and light chains.&#10;B) light chain.&#10;C) epitope.&#10;D) sequence at the amino terminal end of the heavy and light chains.

Accepted Answer

The answer of The component of an immunoglobulin molecule that...

Question 13

A substance that cannot elicit an immune response alone but that must be conjugated to a carrier molecule to cause antibody production is referred to as a(n):&#10;A) antigen.&#10;B) immunogen.&#10;C) hapten.&#10;D) conjugate.

Accepted Answer

The answer of A substance that cannot elicit an immune...

Question 14

What information does crossed immunoelectrophoresis provide that basic immunofixation does not?&#10;A) It provides a qualitative immunologic assessment of specific myeloma protein fractions.&#10;B) It provides better resolution of closely related proteins.&#10;C) It specifically traps the immune precipitate within the gel for quantification.&#10;D) It involves initial electrophoresis with transfer of proteins to nitrocellulose and specific antibody binding to each fraction.

Accepted Answer

The answer of What information does crossed immunoelectrophoresis provide that...

Question 15

Which one of the following is considered a quantitative immunoassay?&#10;A) Immunofixation electrophoresis&#10;B) Crossed immunoelectrophoresis&#10;C) Electroimmunoassay&#10;D) Western blotting

Accepted Answer

The answer of Which one of the following is considered...

Question 16

Which one of the following methods is not a quantitative immunoassay method?&#10;A) Nephelometry&#10;B) Counter immunoelectrophoresis (CIE)&#10;C) ELISA&#10;D) Electroimmunoassay

Accepted Answer

The answer of Which one of the following methods is...

Question 17

In an ELISA procedure,the higher the concentration of patient analyte in the test system,the _____ the amount of product formation.&#10;A) less&#10;B) greater

Accepted Answer

The answer of In an ELISA procedure,the higher the concentration...

Question 18

An immunoassay contains an antidigoxin antibody,a digoxin-enzyme conjugate,a substrate,and the sample containing an unknown concentration of digoxin.These components are used in which one of the following immunoassays?

A) ELISA
B) FPIA
C) EMIT
D) Electroimmunoassay

Accepted Answer

The answer of An immunoassay contains an antidigoxin antibody,a digoxin-enzyme...

Question 19

The substance that is typically injected into an animal to elicit an immune response and induce formation of an antibody is the:&#10;A) antibody.&#10;B) immunogen.&#10;C) immunochemical label.&#10;D) enzyme.

Accepted Answer

The answer of The substance that is typically injected into...

Question 20

In the majority of clinical chemistry immunoassays,the analyte of interest in a patient's serum is typically the:&#10;A) antibody.&#10;B) antigen.&#10;C) immunochemical label.&#10;D) labeled antigen.

Accepted Answer

The answer of In the majority of clinical chemistry immunoassays,the...

Deck 15: Immunochemical Techniques