Question 1

Which of the following best describes the difference between active and passive immunity?

Accepted Answer

Active immunity results from the body’s own immune response to antigens, while passive immunity results from the transfer of antibodies from another individual.

Question 2

A child receives a vaccine containing inactivated fragments of a virus. Which type of vaccine is this?

Accepted Answer

Subunit vaccine

Question 3

Which of the following is a major advantage of attenuated (live) vaccines?

Accepted Answer

They stimulate a strong, long-lasting immune response and can provide contact immunity.

Question 4

A patient is given an injection of gamma globulin after exposure to hepatitis A. What type of immunity is this?

Accepted Answer

Artificial passive immunity

Question 5

Which of the following best explains why multiple doses are often required for inactivated and toxoid vaccines?

Accepted Answer

They possess few antigenic determinants and do not replicate in the host.

Question 6

Which serological test would be most appropriate for determining a patient’s blood type?

Accepted Answer

Agglutination

Question 7

A laboratory technician uses an ELISA to detect the presence of antibodies against HIV in a patient’s serum. Which of the following best describes the principle behind this test?

Accepted Answer

An enzyme-linked antibody binds to the patient’s antibodies, and a color change indicates a positive result.

Question 8

Which of the following is a limitation of passive immunotherapy?

Accepted Answer

It can trigger allergic reactions such as serum sickness.

Question 9

A patient’s serum is serially diluted and tested for agglutination with a specific antigen. The highest dilution showing a positive reaction is 1:1,000. What is the antibody titer?

Accepted Answer

$$1:1,000$$

Question 10

Which of the following statements about the use of eggs in vaccine production is correct?

Accepted Answer

Eggs are used to culture viruses for some vaccines, so individuals with egg allergies may need to avoid certain vaccines.

Question 11

Which of the following best describes the principle of a precipitation reaction in serological testing?

Accepted Answer

Soluble antigens and antibodies form large, insoluble complexes when mixed in optimal proportions.

Question 12

A newborn tests positive for HIV antibodies by ELISA, but six months later, the test is negative. What is the most likely explanation?

Accepted Answer

The initial antibodies were passively acquired from the mother and have since degraded.

Question 13

Which of the following is a reason why parents should continue to vaccinate their children even when a disease is rare in their community?

Accepted Answer

Maintaining high vaccination rates prevents outbreaks and protects those who cannot be vaccinated (herd immunity).

Question 14

Which of the following best describes the function of adjuvants in vaccines?

Accepted Answer

They increase the effective antigenicity of the vaccine.

Question 15

Which of the following serological tests is most appropriate for confirming an HIV infection?

Accepted Answer

Immunoblot (Western blot)

Question 16

A patient’s serum neutralizes the cytopathic effect of a virus in cell culture. What does this indicate?

Accepted Answer

The patient’s serum contains antibodies against the virus.

Question 17

Which of the following is a characteristic of an indirect fluorescent antibody test?

Accepted Answer

A fluorescently labeled anti-antibody binds to the patient’s antibody, which is bound to the antigen.

Question 18

Which of the following is a benefit of using ELISA in diagnostic testing?

Accepted Answer

It is sensitive, can quantify antigen or antibody, and is easy to automate.

Question 19

Which of the following best describes the use of immunochromatographic assays?

Accepted Answer

They are rapid, easy-to-read tests commonly used for pregnancy and rapid infection identification.

Question 20

Which of the following is a potential risk associated with attenuated vaccines?

Accepted Answer

They can revert to a virulent form and cause disease in susceptible individuals.

Chapter 17: Immunization and Immune Testing

Study Guide - Practice Questions

Study Guide - Flashcards