Question 1

Which of the following best describes the role of interferons (IFNs) in the innate immune response to intracellular viruses?

Accepted Answer

They induce an antiviral state in neighboring cells and activate NK cells.

Question 2

Natural Killer (NK) cells are activated in the absence of which molecule on the surface of target cells?

Accepted Answer

MHC class I

Question 3

A patient is infected with a virus that downregulates MHC class I on host cells. Which immune cell type is most likely to target and destroy these infected cells?

Accepted Answer

Natural Killer (NK) cells

Question 4

Which of the following is a key function of perforin and granzymes released by cytotoxic lymphocytes?

Accepted Answer

Induction of apoptosis in virus-infected cells

Question 5

Inflammation is triggered during the immune response to viral infection. Which cytokine is most commonly associated with the induction of inflammation?

Accepted Answer

Tumor necrosis factor-alpha (TNF-α)

Question 6

Which of the following steps is essential for the activation of a CD8+ T cell?

Accepted Answer

Binding to antigen presented by MHC class I molecules and receiving co-stimulatory signals

Question 7

After activation, how does a CD8+ T cell detect and kill virally infected cells?

Accepted Answer

By releasing perforin and granzymes to induce apoptosis in infected cells

Question 8

Which of the following best describes the activation of a T-dependent B cell?

Accepted Answer

It requires help from a CD4+ T cell that recognizes the same antigen presented by MHC class II.

Question 9

How do antibodies produced by activated B cells help protect against disease?

Accepted Answer

By neutralizing pathogens and marking them for destruction by phagocytes

Question 10

Which of the following is an example of a current mRNA vaccine and its main advantage?

Accepted Answer

COVID-19 vaccine (Pfizer-BioNTech or Moderna); induces strong immune response without using live virus

Question 11

What is the typical administration schedule for the Pfizer-BioNTech COVID-19 mRNA vaccine?

Accepted Answer

Two doses spaced 3-4 weeks apart, with possible booster doses

Question 12

Which of the following is a common myth about mRNA vaccines, and why is it incorrect?

Accepted Answer

mRNA vaccines alter your DNA; this is incorrect because mRNA does not enter the cell nucleus or interact with DNA.

Question 13

Why are high vaccination rates important for public health?

Accepted Answer

They help achieve herd immunity, reducing the spread of disease even among unvaccinated individuals.

Question 14

A patient receives a vaccine that contains inactivated virus. Which type of immunity is primarily generated?

Accepted Answer

Humoral immunity (antibody-mediated)

Question 15

Which equation best represents the probability $P$ of herd immunity in a population, given the basic reproduction number $R_0$?

Accepted Answer

$P = 1 - \frac{1}{R_0}$

Question 16

Which of the following is NOT a scientifically supported reason for vaccine effectiveness?

Accepted Answer

Vaccines work by directly killing pathogens in the bloodstream.

Question 17

A child receives a vaccine and later is exposed to the same pathogen. Which immune response is most responsible for the rapid elimination of the pathogen?

Accepted Answer

Secondary (memory) immune response

Question 18

Which of the following statements about inflammation is correct?

Accepted Answer

Inflammation helps recruit immune cells to the site of infection.

Question 19

Which process allows antibodies to neutralize viruses and prevent them from infecting host cells?

Accepted Answer

Neutralization

Question 20

A person claims that vaccines are unnecessary because natural infection provides better immunity. Which scientific argument best refutes this claim?

Accepted Answer

Vaccines provide immunity without the risk of severe disease or complications.

Immune Responses to Viruses and Vaccination: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards