Exam 2 Immunology Ch. 10 - Precipitation and Agglutination Reactions - Quiz

If crossed lines result in an Ouchterlony immunodiffusion reaction with antigens A and B, this indicates that antigens A and B:

-share a common epitope, with B being a more complex antigen.

-are entirely different.

-share a common epitope, with A being a more complex antigen.

-are identical.

are entirely different.

A patient's serum sample is added to a solution containing particulate antigen, but no agglutination is observed. What should be done next?

-Perform serial dilutions of the sample.

-Report out as a negative test.

-Read the reaction in dim light.

-Add more particulate antigen.

Perform serial dilutions of the sample.

A radial immunodiffusion test is run for 72 hours. The concentration of the antigen is then calculated using the:

-log of the diameter of the precipitation ring.

-radius of the precipitation ring.

-square of the diameter of the precipitation ring.

-diameter of the precipitation ring.

square of the diameter of the precipitation ring.

The measurement of light scattered at an angle by the antigen-antibody complexes in a solution is called:

-equivalency.

-agglutination.

-nephelometry.

-turbidimetry.

nephelometry.

If the concentration of free antibody (Ab) = 3 mol/L, the concentration of free antigen (Ag) = 2 mol/L, and the concentration of antigen-antibody complex = 6 mol/L, then the equilibrium constant K equals:

-9.

-1.

-4.

-2.

1.

If an Ouchterlony immunodiffusion pattern shows an arc equidistant between antigens A and B, this indicates that the antigens:

-share a common epitope, with A being a more complex antigen.

-share a common epitope, with B being a more -complex antigen.

-are identical.

-are entirely different.

are identical.

When carrier particles are coated with an antigen that is not normally found on them, this is known as:

-direct agglutination.

-hemagglutination.

-reverse passive agglutination.

-passive agglutination.

passive agglutination.

Based on the following equilibrium constants, which assay would have the best sensitivity?

-K = 9

-K = 2

-K = 4

-K = 1

K = 9

Which antibody has the highest avidity for an antigen?

-Secretory IgA containing Fab that each have an affinity of 4 ´ 10-8/M

-IgG containing Fab that each have an affinity of 4 ´ 10-8/M

-IgE containing Fab that each have an affinity of 1 ´ 10-9

-IgM containing Fab that each have an affinity of 1 ´ 10-8/M

Secretory IgA containing Fab that each have an affinity of 4 ´ 10-8/M

In an agglutination reaction, the antibody isotype that most effectively overcomes the electrostatic repulsion between particles is:

-IgM.

-IgG.

-IgE.

-IgA.

IgM.

The process by which particulate antigens such as cells aggregate to form larger complexes when specific antibody is present is called:

-flocculation.

-agglutination.

-precipitation.

-sensitization.

agglutination.

The particle-counting immunoassay method counts the number of:

-free latex particles.

-antigen-antibody bonds.

-agglutinated particles.

-free antibody molecules.

free latex particles.

If an Ouchterlony immunodiffusion pattern shows an arc between antigens A and B with an extended line pointing to antigen B, this indicates that the antigens:

-are entirely different.

-share a common epitope, with A being a more complex antigen.

-are identical.

-share a common epitope, with B being a more complex antigen.

share a common epitope, with A being a more complex antigen.

Which antibody class may require the use of an enhancement technique to visualize the reaction?

-IgM

-IgE

-IgG

-IgA

IgG

If antibody is uniformly distributed in a gel and antigen is added to a well cut into the gel, the process is called:

-immunofixation.

-retrodiffusion.

-single diffusion.

-double diffusion.

single diffusion.

In performing blood typing using the tube method, if the red cell button is not resuspended properly, what are the most likely results?

-False positive

-Makes the reaction weaker

-Does not affect the results

-False negative

False positive

Agglutination reactions run at room temperature are appropriate for antigen-antibody reactions involving:

-IgA.

-IgM.

-IgE.

-IgG.

IgM.

A serological reaction is set up in which the antigen is bound to a large carrier, the antibody is soluble, and the antigen and carrier bind and form an insoluble complex that is detected macroscopically. What type of assay is described?

-Flocculation

-Precipitation

-Agglutination

-Neutralization

Agglutination

A solution has 4 pentomeric IgM antibodies per microliter. What concentration of antigen molecules is necessary for the solution to be in the zone of equivalence? The antigen has 4 identical epitopes on each molecule.

-4 antigen molecules per microliter

-10 antigen molecules per microliter

-5 antigen molecules per microliter

-20 antigen molecules per microliter

10 antigen molecules per microliter?

The assembly of particles into visible clumps is called:

-sensitization.

-agglutination.

-precipitation.

-equivalence.

agglutination.

The end-point radial immunodiffusion assay:

-can be converted to a kinetic method by application of electrical current.

-requires only a negative control for interpretation.

-is read after antigen-antibody equivalence is reached.

-is the most rapid immunodiffusion method.

is read after antigen-antibody equivalence is reached.

The law of mass action states that:

-free reactants are in equilibrium with bound reactants.

-the rate of binding equals the rate of dissociation.

-the number of antibody binding sites must equal the number of antigen binding sites.

-any free reactants will rapidly bind together.

free reactants are in equilibrium with bound reactants.

The production of insoluble complexes that absorb or scatter light but are too small to see directly is called:

-agglutination.

-sensitization.

-precipitation.

-equivalence.

precipitation.

Which best describes hemagglutination tests?

-Hemoglobin binds to antigen.

-Patient antibody is always involved.

-The reaction involves red blood cells.

-Patient antibody reacts with hemoglobin.

The reaction involves red blood cells.

Which best characterizes agglutination inhibition reactions?

-The antigen is naturally expressed on particles.

-Antigen molecules are artificially bound to particles.

-Antibody is attached to particles.

-No agglutination indicates a positive result.

No agglutination indicates a positive result.

In immunofixation electrophoresis, antisera is:

-applied on the top surface of the gel.

-distributed uniformly throughout the gel.

-driven through the gel by application of electrical current.

-added to troughs cut into the gel.

applied on the top surface of the gel.

The visibility of an agglutination reaction involving IgG can be enhanced by adjusting which factor?

-Adding anti-human Fc

-Decreasing the light to read the reaction

-Changing to a colder temperature

-Diluting out the particulate antigen

Adding anti-human Fc

Rate nephelometry measures the change in what factor over time?

-Antigen breakdown

-Antibody concentration

-Antigen-antibody complex formation

-Antigen concentration

Antigen-antibody complex formation

Which of the following is true of a reverse agglutination test?

-Antibody is attached to particles.

-The antigen-antibody reaction is competitive (no agglutination indicates a positive result).

-The antigen is a natural particle.

-Antigen molecules are artificially bound to particles.

Antibody is attached to particles.

A serological test that uses red blood cells coated with exogenous antigens such as bacterial polysaccharides as a method to detect patient antibodies against those exogenous antigens is called:

-complement fixation.

-neutralization.

-hemagglutination.

-latex agglutination.

hemagglutination.

The AFFINITY of antigen-antibody binding is influenced by which of the following?

-The number of antigens in the reaction

-How well the antigen fits into the binding site on Fab

-The charge distribution on Fc

-The number of Fab sites on the immunoglobulin

How well the antigen fits into the binding site on Fab

If a serum sample does not cause agglutination when mixed with a particular antigen, then you should:

-increase the particle surface charge by altering the pH.

-decrease the viscosity of the sample.

-report that the patient does not have antibody against that antigen.

-test a more diluted sample to overcome possible prozone effects.

test a more diluted sample to overcome possible prozone effects.

Which of the following is characteristic of a passive agglutination test?

-The antigen is naturally found on particles.

-Antigen molecules are artificially bound to particles.

-Antibody is attached to particles.

-The antigen-antibody reaction is competitive (no agglutination indicates a positive result).

Antigen molecules are artificially bound to particles.

Coombs reagent is used for what purpose?

-To enhance agglutination with IgM-coated red blood cells

-To enhance agglutination with IgG-coated red blood cells

-To cause a precipitation reaction with small amounts of antibody

-To link small antigens on patient red cells

To enhance agglutination with IgG-coated red blood cells

When a patient's red blood cells combine with anti-A typing serum to produce a positive result, this reaction is known as:

-hemagglutination.

-passive agglutination.

-flocculation.

-reverse passive agglutination.

hemagglutination.