Question 1

Which of the following best defines a vaccine?

Accepted Answer

A preparation of weakened or killed microorganisms, or parts of microorganisms, administered to induce immunity against a specific disease.

Question 2

Why does vaccination work to prevent infectious diseases?

Accepted Answer

It stimulates the immune system to produce memory cells that recognize and respond rapidly to future exposures to the pathogen.

Question 3

Which of the following is an example of an attenuated vaccine?

Accepted Answer

The measles, mumps, and rubella (MMR) vaccine

Question 4

Which statement correctly contrasts nucleic acid vaccines and recombinant vector vaccines?

Accepted Answer

Nucleic acid vaccines introduce DNA or RNA encoding the antigen directly, while recombinant vector vaccines use a harmless virus or bacterium to deliver the gene encoding the antigen.

Question 5

Which of the following best describes an adjuvant?

Accepted Answer

A substance added to a vaccine to enhance the body's immune response to the antigen.

Question 6

A diagnostic test has a sensitivity of 95% and a specificity of 90%. What does this mean?

Accepted Answer

The test correctly identifies 95% of true positives and 90% of true negatives.

Question 7

Which of the following is a key advantage of monoclonal antibodies over conventional antibody production?

Accepted Answer

They are highly specific to a single epitope and can be produced in unlimited quantities.

Question 8

In a precipitation reaction, what is the principle behind the visible formation of a precipitate?

Accepted Answer

Soluble antigens react with antibodies to form insoluble complexes that precipitate out of solution.

Question 9

Which of the following best differentiates direct from indirect agglutination tests?

Accepted Answer

Direct agglutination uses naturally particulate antigens, while indirect agglutination uses particles coated with antigens or antibodies.

Question 10

Which of the following statements about hemagglutination is correct?

Accepted Answer

It is the clumping of red blood cells due to the interaction with specific antibodies or viruses.

Question 11

A neutralization test is used to detect the presence of antibodies against a virus. Which result indicates a positive test?

Accepted Answer

The virus is unable to infect cells in the presence of the patient's serum.

Question 12

Which of the following best describes the complement-fixation test?

Accepted Answer

It detects the presence of specific antibodies by measuring whether complement is consumed in an antigen-antibody reaction.

Question 13

Which statement best differentiates direct from indirect fluorescent-antibody tests?

Accepted Answer

Direct tests use labeled antibodies that bind directly to the antigen, while indirect tests use a secondary labeled antibody to detect the primary antibody bound to the antigen.

Question 14

In an indirect ELISA test for HIV, which of the following steps is essential for detecting the presence of anti-HIV antibodies in a patient's serum?

Accepted Answer

Adding an enzyme-linked secondary antibody that binds to human antibodies, followed by a substrate that produces a color change.

Question 15

Which of the following best explains how Western blotting works in the diagnosis of infectious diseases?

Accepted Answer

Proteins are separated by size using electrophoresis, transferred to a membrane, and detected with specific antibodies.

Question 16

The rapid antigen test for COVID-19 is based on which principle?

Accepted Answer

Detection of viral antigens using antibodies immobilized on a test strip, producing a visible line if the antigen is present.

Question 17

Which of the following statements about the value and risks of vaccines is most accurate?

Accepted Answer

Vaccines provide significant public health benefits by preventing disease, and the risks of serious adverse effects are extremely low compared to the benefits.

Question 18

A patient receives a subunit vaccine. Which of the following best describes what is contained in this vaccine?

Accepted Answer

Purified components of the pathogen, such as proteins or polysaccharides, but not the whole organism.

Question 19

Which of the following scenarios best illustrates the difference between agglutination and precipitation tests?

Accepted Answer

Agglutination tests involve the clumping of particulate antigens, such as cells, while precipitation tests involve the formation of insoluble complexes from soluble antigens and antibodies.

Question 20

A laboratory is developing a new diagnostic test for a rare disease. Which of the following best describes why high specificity is important in this context?

Accepted Answer

High specificity ensures that individuals without the disease are not incorrectly identified as positive, reducing false positives.

Practical Applications of Immunology: Vaccines and Diagnostic Tests

Study Guide - Practice Questions

Study Guide - Flashcards