The immune system protects the body from pathogens and plays a crucial role in health and disease. It involves a complex network of cells, tissues, and molecules that identify and eliminate threats. This quiz, aligned with Pharm.D. coursework such as PHA5561 and PHA5515, tests your understanding of both innate and adaptive immunity, immune cells, and immune-mediated diseases.
1. The first line of defense in the immune system includes:
- A. B cells
- B. Skin and mucous membranes
- C. T cells
- D. Antibodies
Correct answer: B. Skin and mucous membranes
2. Which cells are primarily responsible for humoral immunity?
- A. T cells
- B. Macrophages
- C. B cells
- D. Dendritic cells
Correct answer: C. B cells
3. Helper T cells recognize antigens presented by:
- A. MHC class I molecules
- B. MHC class II molecules
- C. Natural killer cells
- D. Plasma cells
Correct answer: B. MHC class II molecules
4. The process by which neutrophils migrate to the site of infection is called:
- A. Phagocytosis
- B. Chemotaxis
- C. Clonal selection
- D. Diapedesis
Correct answer: B. Chemotaxis
5. Which immunoglobulin is most abundant in circulation?
- A. IgA
- B. IgM
- C. IgE
- D. IgG
Correct answer: D. IgG
6. Which immune cells are responsible for killing virus-infected cells?
- A. B cells
- B. Helper T cells
- C. Cytotoxic T cells
- D. Mast cells
Correct answer: C. Cytotoxic T cells
7. Antigen-presenting cells include:
- A. Neutrophils
- B. Erythrocytes
- C. Dendritic cells
- D. Basophils
Correct answer: C. Dendritic cells
8. Which cytokine is primarily involved in the acute-phase response?
- A. IL-2
- B. IL-6
- C. IFN-γ
- D. IL-4
Correct answer: B. IL-6
9. The complement system is part of which immune response?
- A. Adaptive immunity
- B. Cell-mediated immunity
- C. Innate immunity
- D. Delayed-type hypersensitivity
Correct answer: C. Innate immunity
10. What is opsonization?
- A. Antibody production
- B. Enhancement of phagocytosis by marking pathogens
- C. Release of histamine
- D. Cytotoxic killing of parasites
Correct answer: B. Enhancement of phagocytosis by marking pathogens
11. Which immunoglobulin is primarily responsible for allergic responses?
- A. IgG
- B. IgA
- C. IgE
- D. IgM
Correct answer: C. IgE
12. The thymus is the site of maturation for:
- A. B cells
- B. T cells
- C. Macrophages
- D. Natural killer cells
Correct answer: B. T cells
13. Toll-like receptors (TLRs) are important in recognizing:
- A. Antibodies
- B. Self-antigens
- C. Pathogen-associated molecular patterns (PAMPs)
- D. MHC molecules
Correct answer: C. Pathogen-associated molecular patterns (PAMPs)
14. Which of the following is a professional antigen-presenting cell?
- A. Eosinophil
- B. Neutrophil
- C. Dendritic cell
- D. Mast cell
Correct answer: C. Dendritic cell
15. Regulatory T cells help to:
- A. Destroy infected cells
- B. Activate macrophages
- C. Suppress immune responses
- D. Stimulate antibody production
Correct answer: C. Suppress immune responses
16. The lymphoid organs include all EXCEPT:
- A. Thymus
- B. Spleen
- C. Bone marrow
- D. Liver
Correct answer: D. Liver
17. Which of the following is part of the adaptive immune response?
- A. Complement cascade
- B. Natural killer cells
- C. T lymphocytes
- D. Skin barrier
Correct answer: C. T lymphocytes
18. Which molecule on antigen-presenting cells presents antigen to CD8+ T cells?
- A. MHC class I
- B. MHC class II
- C. CD28
- D. TCR
Correct answer: A. MHC class I
19. Natural killer (NK) cells recognize and destroy cells that:
- A. Overexpress MHC I
- B. Lack MHC I
- C. Produce antibodies
- D. Are helper T cells
Correct answer: B. Lack MHC I
20. The primary response to a new antigen is dominated by which immunoglobulin?
- A. IgG
- B. IgE
- C. IgA
- D. IgM
Correct answer: D. IgM
21. Which organ filters blood and removes old red blood cells?
- A. Thymus
- B. Lymph nodes
- C. Spleen
- D. Bone marrow
Correct answer: C. Spleen
22. Delayed-type hypersensitivity is mediated by:
- A. IgE
- B. Neutrophils
- C. Cytotoxic T cells
- D. Helper T cells
Correct answer: D. Helper T cells
23. The process by which B cells produce different classes of antibodies is called:
- A. VDJ recombination
- B. Somatic hypermutation
- C. Isotype switching
- D. Clonal deletion
Correct answer: C. Isotype switching
24. Which of the following is a primary lymphoid organ?
- A. Lymph node
- B. Spleen
- C. Thymus
- D. Tonsil
Correct answer: C. Thymus
25. Which immunoglobulin is found in mucosal secretions?
- A. IgE
- B. IgM
- C. IgG
- D. IgA
Correct answer: D. IgA
26. What is the role of memory B cells?
- A. Produce complement proteins
- B. Phagocytose pathogens
- C. Initiate immediate response upon re-exposure
- D. Activate cytotoxic T cells
Correct answer: C. Initiate immediate response upon re-exposure
27. The CD4 molecule is found on which cell type?
- A. Cytotoxic T cells
- B. Helper T cells
- C. B cells
- D. NK cells
Correct answer: B. Helper T cells
28. Which of the following is a cytokine that activates macrophages?
- A. IL-4
- B. IL-10
- C. IFN-γ
- D. IL-6
Correct answer: C. IFN-γ
29. Autoimmunity results from failure of:
- A. Inflammation
- B. Antibody synthesis
- C. Immune tolerance
- D. Complement activation
Correct answer: C. Immune tolerance
30. What type of immunity is conferred by vaccination?
- A. Passive natural
- B. Passive artificial
- C. Active natural
- D. Active artificial
Correct answer: D. Active artificial
31. Which hypersensitivity type is mediated by IgG or IgM against cell surface antigens?
- A. Type I
- B. Type II
- C. Type III
- D. Type IV
Correct answer: B. Type II
32. Which enzyme is involved in antigen processing for MHC I presentation?
- A. RNA polymerase
- B. Reverse transcriptase
- C. Proteasome
- D. Kinase
Correct answer: C. Proteasome
33. Anaphylaxis is associated with massive release of:
- A. Cytokines
- B. Histamine
- C. Complement
- D. IFN-γ
Correct answer: B. Histamine
34. Which structure allows immune cell communication?
- A. Antigen
- B. MHC
- C. Cytokine
- D. Immunoglobulin
Correct answer: C. Cytokine
35. Which complement pathway is activated by antigen-antibody complexes?
- A. Alternative
- B. Lectin
- C. Classical
- D. Terminal
Correct answer: C. Classical
36. Which T cell subtype directly kills infected or cancerous cells?
- A. Helper T cell
- B. Regulatory T cell
- C. Cytotoxic T cell
- D. Memory T cell
Correct answer: C. Cytotoxic T cell
37. What is the function of the Fc region of an antibody?
- A. Antigen recognition
- B. Neutralization
- C. Complement activation and binding to immune cells
- D. Variable binding
Correct answer: C. Complement activation and binding to immune cells
38. Which of the following is involved in central tolerance?
- A. Clonal expansion
- B. Somatic hypermutation
- C. Clonal deletion in thymus or bone marrow
- D. Class switching
Correct answer: C. Clonal deletion in thymus or bone marrow
39. Which component of the immune system recognizes a specific antigen?
- A. Macrophage
- B. T-cell receptor
- C. Complement C3
- D. Toll-like receptor
Correct answer: B. T-cell receptor
40. The Fab region of an antibody is responsible for:
- A. Binding to Fc receptors
- B. Binding to antigens
- C. Activating complement
- D. Crossing the placenta
Correct answer: B. Binding to antigens
41. In transplant rejection, the immune system targets:
- A. Autoantigens
- B. Pathogens
- C. Alloantigens
- D. Toxins
Correct answer: C. Alloantigens
42. Which cells secrete antibodies?
- A. Plasma cells
- B. Helper T cells
- C. Cytotoxic T cells
- D. Macrophages
Correct answer: A. Plasma cells
43. What is the term for the ability to distinguish self from non-self?
- A. Immunogenicity
- B. Self-tolerance
- C. Allergenicity
- D. MHC restriction
Correct answer: B. Self-tolerance
44. Which condition is an example of a primary immunodeficiency?
- A. AIDS
- B. Systemic lupus erythematosus
- C. DiGeorge syndrome
- D. Rheumatoid arthritis
Correct answer: C. DiGeorge syndrome
45. Which interleukin promotes B cell proliferation?
- A. IL-2
- B. IL-4
- C. IL-6
- D. IL-12
Correct answer: B. IL-4
46. Which structure is responsible for T cell education?
- A. Bone marrow
- B. Lymph node
- C. Thymus
- D. Spleen
Correct answer: C. Thymus
47. What is the result of complement C3 deficiency?
- A. Increased allergy
- B. Reduced inflammation
- C. Impaired opsonization
- D. Autoimmunity
Correct answer: C. Impaired opsonization
48. The main function of lymph nodes is to:
- A. Produce erythrocytes
- B. Store calcium
- C. Filter lymph and trap antigens
- D. Transport oxygen
Correct answer: C. Filter lymph and trap antigens
49. Which immune cells express CD8?
- A. Helper T cells
- B. Cytotoxic T cells
- C. B cells
- D. Natural killer cells
Correct answer: B. Cytotoxic T cells
50. Which antibody is produced first in a primary immune response?
- A. IgG
- B. IgA
- C. IgE
- D. IgM
Correct answer: D. IgM