Q: Which equation best represents the classical complement activation triggered by immune complexes in Type III hypersensitivity?

$$\text{Ag} + \text{Ab} \rightarrow \text{Ag-Ab complex} \rightarrow \text{Complement activation}$$

Q: Which equation best represents the neutralization of an exotoxin by an antitoxin antibody?

$$\text{Toxin} + \text{Antitoxin} \rightarrow \text{Neutralized complex}$$

Question 1

Which hypersensitivity type is characterized by IgE-mediated mast cell degranulation and is responsible for allergic reactions such as hay fever and anaphylaxis?

Accepted Answer

Type I (Immediate hypersensitivity)

Question 2

A patient develops a rash 24-48 hours after exposure to poison ivy. Which immune mechanism is primarily responsible for this reaction?

Accepted Answer

Cell-mediated response involving Th1 cells and macrophages

Question 3

Which of the following best describes the mechanism of superantigens?

Accepted Answer

They bind outside the T cell receptor and MHC complex, causing massive T cell activation and cytokine release.

Question 4

Which autoimmune disease is caused by autoantibodies against acetylcholine receptors on skeletal muscle?

Accepted Answer

Myasthenia gravis

Question 5

A newborn receives IgA antibodies from breast milk. What type of immunity is this?

Accepted Answer

Natural passive immunity

Question 6

Which vaccine type uses a chemically modified exotoxin that retains antigenicity but loses toxicity?

Accepted Answer

Toxoid vaccine

Question 7

What is the primary mechanism by which herd immunity protects a population?

Accepted Answer

It reduces the number of susceptible individuals, blocking disease transmission.

Question 8

Which hypersensitivity type involves IgG interaction with soluble or circulating antigens, leading to immune complex formation and tissue deposition?

Accepted Answer

Type III (Immune complex hypersensitivity)

Question 9

A patient is treated with rattlesnake antivenom after a bite. What type of immunity is provided?

Accepted Answer

Artificial passive immunity

Question 10

Which equation best represents the classical complement activation triggered by immune complexes in Type III hypersensitivity?

Accepted Answer

$$	ext{Ag} + 	ext{Ab} ightarrow 	ext{Ag-Ab complex} ightarrow 	ext{Complement activation}$$

Question 11

Which of the following is a real-world example of a disease prevented by a conjugate vaccine?

Accepted Answer

Haemophilus influenzae type b (Hib) meningitis

Question 12

Which of the following statements about active immunity is correct?

Accepted Answer

It involves exposure to antigen and results in immune memory.

Question 13

Which vaccine type is most effective for viral immunity and involves administration of attenuated strains?

Accepted Answer

Live attenuated virus vaccine

Question 14

A child receives the MMR vaccine. Which viruses are they being immunized against?

Accepted Answer

Measles, mumps, rubella

Question 15

Which of the following is a plausible reason for the resurgence of measles cases in the United States in 1990?

Accepted Answer

Only 70% of children were immunized, reducing herd immunity.

Question 16

Which equation best represents the neutralization of an exotoxin by an antitoxin antibody?

Accepted Answer

$$	ext{Toxin} + 	ext{Antitoxin} ightarrow 	ext{Neutralized complex}$$

Question 17

Which hypersensitivity type is most likely involved in the tuberculin skin test, which produces a delayed reaction?

Accepted Answer

Type IV (Delayed-type hypersensitivity)

Question 18

Which of the following is NOT a characteristic of passive immunity?

Accepted Answer

Immune memory is generated and maintained

Question 19

Which of the following is a genetically engineered vaccine that uses a pathogen gene inserted into a harmless host to produce antigen?

Accepted Answer

Recombinant antigen vaccine

Question 20

A patient with systemic lupus erythematosus (SLE) has autoantibodies against DNA and other cellular constituents. Which hypersensitivity mechanism is primarily involved?

Accepted Answer

Type III (Immune complex hypersensitivity)

Immune Response Diseases and Preventable Diseases: Hypersensitivities, Autoimmunity, and Vaccination

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