Question 1

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

Accepted Answer

Active immunization requires the patient to mount an adaptive immune response after receiving antigens, while passive immunization provides immediate protection by transferring preformed antibodies.

Question 2

Edward Jenner is credited with which major advancement in immunization history?

Accepted Answer

Developing the first vaccine against smallpox using cowpox material.

Question 3

Which of the following is a major reason why some developing nations have low vaccination rates?

Accepted Answer

Vaccine-associated risks discourage investment in new vaccines.

Question 4

Attenuated (modified live) vaccines are characterized by which of the following?

Accepted Answer

They use pathogens with reduced virulence, which can stimulate a strong immune response and provide contact immunity.

Question 5

What is the primary function of an adjuvant in a vaccine?

Accepted Answer

To increase the effective antigenicity of the vaccine.

Question 6

A patient with an egg allergy should avoid which type of vaccine?

Accepted Answer

Vaccines cultured in chicken eggs, such as some influenza vaccines.

Question 7

Which equation best represents the relationship between antibody concentration and agglutination titer?

Accepted Answer

The titer is the highest dilution of serum that still causes agglutination: $$	ext{Titer} = \frac{1}{	ext{highest dilution with positive agglutination}}$$

Question 8

Which serological test is most appropriate for diagnosing syphilis using precipitation reactions?

Accepted Answer

Immunodiffusion (precipitation) test

Question 9

During a precipitation test, what happens if there is an excess of antibody?

Accepted Answer

Precipitation does not occur because immune complexes are too small and soluble.

Question 10

Which of the following statements about ELISA is FALSE?

Accepted Answer

ELISA has low sensitivity compared to other serological tests.

Question 11

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

Accepted Answer

The newborn initially had maternal antibodies, which were degraded over time.

Question 12

Which of the following is detected in a pregnancy test using immunochromatographic assay?

Accepted Answer

Human chorionic gonadotropin (hCG)

Question 13

Which of the following is a safety concern associated with vaccines?

Accepted Answer

All of the above

Question 14

Which serological test uses fluorescently labeled antibodies to detect antigens in patient tissues?

Accepted Answer

Direct fluorescent antibody test

Question 15

Which of the following best describes herd immunity?

Accepted Answer

Indirect protection from infectious disease when a population is immune through vaccination or previous infection.

Question 16

Which equation describes the relationship between antigen and antibody in a precipitation reaction?

Accepted Answer

Precipitation occurs at optimal proportions: $$	ext{Precipitate} \propto 	ext{[Antigen]} 	imes 	ext{[Antibody]}$$ when both are balanced.

Question 17

Which serological test is most commonly used to confirm HIV infection?

Accepted Answer

Immunoblot (western blot)

Question 18

Which of the following is NOT an advantage of point-of-care testing?

Accepted Answer

The assays are quantitative.

Question 19

Which serological test is used to measure the cloudiness of a solution to quantify proteins in serum?

Accepted Answer

Turbidimetric and nephelometric tests

Ch 17 Immunization and Immune Testing: Microbiology Study Guide

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