Biology Test Immunology 2 — Questions and Answers
Question 1: Which type of hypersensitivity reaction involves IgE-mediated mast cell degranulation?
- Type I (Correct answer)
- Type II
- Type III
- Type IV
Correct answer: Type I
Type I hypersensitivity (immediate hypersensitivity) involves IgE antibodies bound to mast cells, which degranulate upon allergen re-exposure.
Question 2: What is the primary function of regulatory T cells (Tregs)?
- Kill virus-infected cells
- Suppress immune responses to prevent autoimmunity (Correct answer)
- Produce antibodies
- Present antigens to B cells
Correct answer: Suppress immune responses to prevent autoimmunity
Regulatory T cells suppress excessive immune responses and maintain self-tolerance, preventing autoimmune diseases.
Question 3: Which complement pathway is activated by mannose-binding lectin (MBL)?
- Classical pathway
- Alternative pathway
- Lectin pathway (Correct answer)
- Terminal pathway
Correct answer: Lectin pathway
The lectin pathway is activated when mannose-binding lectin recognizes mannose residues on microbial surfaces.
Question 4: During an immune response, affinity maturation occurs in which structure?
- Thymus
- Bone marrow
- Germinal centers of lymph nodes (Correct answer)
- Spleen red pulp
Correct answer: Germinal centers of lymph nodes
Affinity maturation occurs in germinal centers where B cells undergo somatic hypermutation and selection for higher-affinity antibodies.
Question 5: Which molecule serves as a co-receptor for CD4+ T cells during antigen recognition?
- CD8
- MHC class I
- MHC class II (Correct answer)
- CD28
Correct answer: MHC class II
CD4 binds to MHC class II molecules on antigen-presenting cells, stabilizing the interaction between the T cell receptor and the antigen-MHC complex.
Question 6: What is opsonization in the context of innate immunity?
- Killing bacteria with reactive oxygen species
- Coating pathogens with antibodies or complement to enhance phagocytosis (Correct answer)
- Releasing cytokines to recruit neutrophils
- Forming membrane attack complexes on bacteria
Correct answer: Coating pathogens with antibodies or complement to enhance phagocytosis
Opsonization involves coating pathogens with opsonins (antibodies or complement proteins like C3b) to enhance recognition and phagocytosis by phagocytes.
Question 7: Which interleukin is primarily responsible for driving the differentiation of naive T cells into Th17 cells?
- IL-4
- IL-12
- TGF-β + IL-6 (Correct answer)
- IFN-γ
Correct answer: TGF-β + IL-6
The combination of TGF-β and IL-6 drives naive T cells to differentiate into Th17 cells, which produce IL-17 and play roles in inflammation and defense against extracellular bacteria.
Biology Test Immunology 2
Which type of hypersensitivity reaction involves IgE-mediated mast cell degranulation?