Question 1

A patient receives a kidney transplant from a genetically unrelated donor. Which immune system component is primarily responsible for recognizing and attacking the foreign tissue, and what is the molecular basis for this recognition?

Accepted Answer

T cells; recognition of non-self MHC molecules on donor cells

Question 2

Which of the following best describes the function of the complement system in the immune response?

Accepted Answer

It lyses pathogens by forming membrane attack complexes.

Question 3

A newborn is at risk for hemolytic disease due to Rh incompatibility. Which antibody class is most responsible for this condition, and what is the mechanism?

Accepted Answer

IgG; crosses the placenta and mediates destruction of fetal RBCs

Question 4

Which of the following is a correct sequence of events in the adaptive immune response to a viral infection?

Accepted Answer

Antigen-presenting cell → Helper T cell activation → B cell activation → Plasma cell antibody production

Question 5

A patient with multiple sclerosis is experiencing demyelination of neurons. Which type of hypersensitivity reaction is most closely associated with this autoimmune disease?

Accepted Answer

Type IV (T cell-mediated delayed response)

Question 6

Which of the following best explains why IgM is the first antibody detected during a primary immune response?

Accepted Answer

IgM is produced rapidly by plasma cells before class switching occurs.

Question 7

A laboratory test shows a high titer of IgE antibodies in a patient with severe hay fever. Which hypersensitivity type and mechanism are involved?

Accepted Answer

Type I; IgE-mediated mast cell degranulation

Question 8

Which of the following best describes the role of MHC II molecules in the immune response?

Accepted Answer

They present exogenous antigens to helper T cells.

Question 9

A patient is exposed to the same pathogen twice. The second exposure results in a faster and stronger antibody response. Which immunological principle explains this phenomenon?

Accepted Answer

The secondary response is dominated by IgG due to memory B cells.

Question 10

Which of the following statements about epidemiological terms is correct?

Accepted Answer

Prevalence measures the total number of existing cases at a given time.

Question 11

A patient with a severe bacterial infection is treated with antibiotics, but the infection persists. Laboratory analysis reveals the bacteria are producing a toxin in the blood. What is the term for this condition?

Accepted Answer

Toxemia

Question 12

Which immune cell type is primarily responsible for killing virus-infected and cancer cells without prior sensitization?

Accepted Answer

Natural killer (NK) cells

Question 13

A patient with type I diabetes mellitus has an autoimmune attack on pancreatic beta cells. Which immune mechanism is most likely involved?

Accepted Answer

Type IV hypersensitivity (T cell-mediated)

Question 14

Which of the following best describes the function of eosinophils in the immune system?

Accepted Answer

They attack parasites and are involved in allergy.

Question 15

A blood transfusion mismatch can cause agglutination and hemolysis. Which antibody class is most likely to mediate this reaction?

Accepted Answer

IgM

Question 16

Which of the following is a correct statement about DNA vaccines?

Accepted Answer

They introduce plasmid DNA that expresses antigenic proteins, inducing an immune response.

Question 17

A patient with systemic lupus erythematosus (SLE) has immune complexes deposited in multiple tissues. Which type of hypersensitivity reaction is this?

Accepted Answer

Type III

Question 18

Which of the following equations correctly represents the calculation of prevalence in epidemiology?

Accepted Answer

$$	ext{Prevalence} = \frac{	ext{Number of existing cases}}{	ext{Total population}}$$

Question 19

Which of the following best describes the function of helper T cells (CD4+)?

Accepted Answer

They activate B cells and cytotoxic T cells by releasing cytokines.

Question 20

A patient with a history of repeated infections is found to have a deficiency in plasma cells. Which of the following is the most likely consequence?

Accepted Answer

Reduced antibody production

Comprehensive Study Notes: Immune System, Pathogens, and Public Health

Study Guide - Practice Questions

Study Guide - Flashcards