Immunology and Host Defense Mechanisms MCQs

1. : Which type of immunity is characterized by the production of antibodies against specific antigens?
(A) Innate immunity
(B) Passive immunity
(C) Adaptive (acquired) immunity
(D) Humoral immunity

2. : What is the primary function of phagocytes in the immune system?
(A) To produce antibodies
(B) To destroy pathogens through engulfment and digestion
(C) To regulate the immune response
(D) To create memory cells

3. : Which cells are primarily involved in cell-mediated immunity?
(A) B cells
(B) T cells
(C) Erythrocytes
(D) Platelets

4. : What is the role of cytotoxic T cells (CD8+ T cells) in the immune response?
(A) To produce antibodies
(B) To activate other immune cells
(C) To directly kill infected cells and cancer cells
(D) To promote inflammation

5. : Which class of immunoglobulins (antibodies) is most commonly found in the blood and provides long-term protection?
(A) IgM
(B) IgA
(C) IgE
(D) IgG

6. : The complement system is a part of which type of immunity?
(A) Innate immunity
(B) Adaptive immunity
(C) Passive immunity
(D) Acquired immunity

7. : What is the primary function of natural killer (NK) cells in the immune system?
(A) To produce antibodies
(B) To phagocytize pathogens
(C) To destroy infected or cancerous cells without prior sensitization
(D) To activate B cells

8. : Which type of hypersensitivity reaction is mediated by IgE antibodies and involves an allergic response?
(A) Type I hypersensitivity
(B) Type II hypersensitivity
(C) Type III hypersensitivity
(D) Type IV hypersensitivity

9. : Which organ is primarily responsible for the maturation of T lymphocytes (T cells)?
(A) Spleen
(B) Bone marrow
(C) Thymus
(D) Lymph nodes

10. : What is the primary role of antigen-presenting cells (APCs) in the immune system?
(A) To destroy pathogens
(B) To present antigens to T cells for activation
(C) To produce antibodies
(D) To regulate inflammation