Question 1

Which of the following best describes the mechanism of action for a Type I (anaphylactic) hypersensitivity reaction?

Accepted Answer

Cross-linking of IgE antibodies on mast cells, resulting in degranulation and release of histamine

Question 2

A patient receives a vaccine containing purified protein from a bacterial pathogen. Which type of vaccine is this?

Accepted Answer

Subunit vaccine

Question 3

Which of the following is an example of artificially acquired passive immunity?

Accepted Answer

Receiving gamma globulin injection after exposure to hepatitis

Question 4

A newborn develops hemolytic disease due to Rh incompatibility. Which type of hypersensitivity reaction is responsible?

Accepted Answer

Type II (Cytotoxic)

Question 5

Which of the following best explains why the SARS-CoV-2 mRNA vaccine is effective?

Accepted Answer

It delivers mRNA encoding the spike protein, leading to antigen production and immune activation

Question 6

A patient develops a red, itchy rash 48 hours after contact with poison ivy. Which hypersensitivity type is this, and what is the main immune cell involved?

Accepted Answer

Type IV; T cells

Question 7

Which of the following vaccines is an example of a live attenuated vaccine?

Accepted Answer

MMR (measles, mumps, rubella) vaccine

Question 8

A patient with systemic lupus erythematosus (SLE) experiences tissue damage due to immune complex deposition. Which hypersensitivity type is this, and what is the key mechanism?

Accepted Answer

Type III; Deposition of antigen-antibody complexes in tissues

Question 9

Which of the following best describes the difference between naturally acquired active immunity and artificially acquired active immunity?

Accepted Answer

Naturally acquired active immunity results from infection or normal exposure, while artificially acquired active immunity results from vaccination

Question 10

A person receives a tuberculin skin test and develops a firm, raised area at the injection site after 48 hours. This reaction is an example of:

Accepted Answer

Type IV hypersensitivity

Question 11

Which of the following best explains why passive immunization provides only short-term protection?

Accepted Answer

It involves the transfer of preformed antibodies that are eventually degraded

Question 12

Which of the following is a key feature of Type II (cytotoxic) hypersensitivity reactions?

Accepted Answer

Involvement of IgG or IgM antibodies and complement activation leading to cell lysis

Question 13

A child receives the inactivated polio vaccine. Which of the following statements is correct regarding this vaccine?

Accepted Answer

It contains killed poliovirus and cannot cause the disease

Question 14

Which of the following best describes the role of T cells in Type IV hypersensitivity reactions?

Accepted Answer

T cells directly lyse target cells and release cytokines to recruit macrophages

Question 15

Which of the following is a real-world example of a Type IV hypersensitivity reaction?

Accepted Answer

Allergic contact dermatitis from nickel jewelry

Question 16

A patient receives a hepatitis B vaccine that contains only a fragment of the viral antigen. What type of vaccine is this?

Accepted Answer

Recombinant subunit vaccine

Question 17

Which of the following equations best represents the relationship between antigen exposure and the secondary immune response?

Accepted Answer

$$IgG_{secondary} = IgG_{primary} 	imes k_{memory}$$

Question 18

Which of the following best explains why booster shots are often required for some vaccines?

Accepted Answer

To stimulate a stronger and faster secondary immune response by activating memory cells

Question 19

A patient with rheumatoid arthritis has antibodies against their own joint tissues. Which type of hypersensitivity is this, and what is the main mechanism?

Accepted Answer

Type III; Immune complex deposition in joints

Question 20

Which of the following best describes the process of desensitization therapy for allergies?

Accepted Answer

Repeated exposure to increasing doses of allergen to shift antibody production from IgE to IgG

Vaccines and Hypersensitivities: Immunological Principles and Disorders

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