Question 1

Which of the following best describes the principle behind herd immunity?

Accepted Answer

It occurs when a critical portion of the population is immune, reducing the spread of infectious disease.

Question 2

A patient receives a vaccine containing inactivated virus particles. Which type of immunity is primarily stimulated?

Accepted Answer

Active artificial immunity

Question 3

Which of the following is a major advantage of live attenuated vaccines compared to killed (inactivated) vaccines?

Accepted Answer

They stimulate a stronger and longer-lasting immune response.

Question 4

A child is given an injection of pre-formed antibodies after exposure to rabies. What type of immunity is this?

Accepted Answer

Passive artificial immunity

Question 5

Which hypersensitivity reaction is mediated by IgE antibodies and is responsible for allergic responses such as hay fever?

Accepted Answer

Type I hypersensitivity

Question 6

A patient develops hemolytic anemia after receiving a mismatched blood transfusion. Which type of hypersensitivity is this?

Accepted Answer

Type II hypersensitivity

Question 7

Which of the following is a characteristic of autoimmune diseases?

Accepted Answer

The immune system fails to recognize self-antigens and attacks the body's own tissues.

Question 8

Which laboratory test is commonly used to detect the presence of antibodies in a patient's serum?

Accepted Answer

ELISA (Enzyme-Linked Immunosorbent Assay)

Question 9

A patient with HIV is found to have a CD4+ T cell count of less than 200 cells/mm$$^3. $$What does this indicate?

Accepted Answer

The patient has progressed to AIDS.

Question 10

Which of the following is a common mechanism by which vaccines confer immunity?

Accepted Answer

Stimulating the production of memory B cells

Question 11

Which of the following equations best represents the calculation for vaccine efficacy ($$VE$$)?

Accepted Answer

$$VE = \frac{(AR_{unvaccinated} - AR_{vaccinated})}{AR_{unvaccinated}} 	imes 100$$

Question 12

A patient develops a rash 48 hours after exposure to poison ivy. Which type of hypersensitivity reaction is this?

Accepted Answer

Type IV hypersensitivity

Question 13

Which of the following is NOT a typical symptom of systemic lupus erythematosus (SLE)?

Accepted Answer

High blood glucose

Question 14

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

Accepted Answer

To maintain a high level of memory cells and antibody titers over time

Question 15

A newborn receives antibodies from its mother through breast milk. What type of immunity is this?

Accepted Answer

Passive natural immunity

Question 16

Which of the following is a key difference between primary and secondary immune responses?

Accepted Answer

Secondary responses are faster and produce higher antibody titers due to memory cells.

Question 17

Which of the following is most likely to cause anaphylactic shock?

Accepted Answer

A type I hypersensitivity reaction to peanuts

Question 18

Which of the following is a common laboratory method for diagnosing HIV infection?

Accepted Answer

ELISA followed by Western blot confirmation

Question 19

Which of the following best describes the mechanism of action for monoclonal antibody therapy in autoimmune diseases?

Accepted Answer

It targets and neutralizes specific immune cells or cytokines involved in the autoimmune response.

Question 20

A patient with a history of repeated infections is found to have low levels of immunoglobulin G (IgG). Which condition is most likely?

Accepted Answer

Immunodeficiency

Chapter 17 & 18 study guide

Guida di studio - Domande di pratica