PCB 3233 Final Exam V2 | PCB 3233
Immunology | Actual Q&A with Rationale
(PCB3233 Exam | University of Central
Florida
1. Which of the following molecules is responsible for the transport of processed cytosolic
peptides into the lumen of the endoplasmic reticulum for MHC Class I loading?
A. Calnexin
B. TAP1/TAP2
C. Invariant Chain
D. HLA-DM
Answer: B
Rationale: The TAP (Transporter associated with antigen processing) complex is essential
for moving peptides from the cytoplasm to the ER. Once inside the ER, these peptides can
be loaded onto nascent MHC class I molecules. This process is distinct from the MHC class II
pathway, which utilizes the invariant chain and HLA-DM for transport.
2. Which complement pathway is activated by the binding of C1q to the Fc regions of IgM or
IgG antibodies?
A. Alternative pathway
B. Classical pathway
,C. Lectin pathway
D. Terminal pathway
Answer: B
Rationale: The classical pathway is initiated when the C1 complex binds to antibody-
antigen complexes. C1q requires at least two Fc regions to become activated and initiate
the proteolytic cascade. This link between the adaptive and innate systems allows targeted
destruction of pathogens.
3. Which cell type is primarily responsible for the production of high-affinity antibodies and
long-lived plasma cells during a germinal center reaction?
A. Dendritic cells
B. NK cells
C. Neutrophils
D. B cells
Answer: D
Rationale: B cells undergo somatic hypermutation and class-switch recombination within
the germinal centers of lymphoid organs. These processes are regulated by follicular helper
T cells and follicular dendritic cells. The result is the selection of B cells with high affinity
for the specific antigen.
, 4. In Type I Hypersensitivity, the primary antibody isotype responsible for mast cell
degranulation is:
A. IgG
B. IgM
C. IgE
D. IgA
Answer: C
Rationale: Type I hypersensitivity involves the production of IgE antibodies in response to
common environmental allergens. These IgE molecules bind to high-affinity Fc receptors
on the surface of mast cells and basophils. Upon re-exposure, the allergen cross-links the
IgE, triggering the release of inflammatory mediators like histamine.
5. Which enzyme is responsible for the recombination of V, D, and J gene segments during
lymphocyte development?
A. AID
B. TdT
C. RAG-1/RAG-2
D. Caspase-3
Answer: C
Immunology | Actual Q&A with Rationale
(PCB3233 Exam | University of Central
Florida
1. Which of the following molecules is responsible for the transport of processed cytosolic
peptides into the lumen of the endoplasmic reticulum for MHC Class I loading?
A. Calnexin
B. TAP1/TAP2
C. Invariant Chain
D. HLA-DM
Answer: B
Rationale: The TAP (Transporter associated with antigen processing) complex is essential
for moving peptides from the cytoplasm to the ER. Once inside the ER, these peptides can
be loaded onto nascent MHC class I molecules. This process is distinct from the MHC class II
pathway, which utilizes the invariant chain and HLA-DM for transport.
2. Which complement pathway is activated by the binding of C1q to the Fc regions of IgM or
IgG antibodies?
A. Alternative pathway
B. Classical pathway
,C. Lectin pathway
D. Terminal pathway
Answer: B
Rationale: The classical pathway is initiated when the C1 complex binds to antibody-
antigen complexes. C1q requires at least two Fc regions to become activated and initiate
the proteolytic cascade. This link between the adaptive and innate systems allows targeted
destruction of pathogens.
3. Which cell type is primarily responsible for the production of high-affinity antibodies and
long-lived plasma cells during a germinal center reaction?
A. Dendritic cells
B. NK cells
C. Neutrophils
D. B cells
Answer: D
Rationale: B cells undergo somatic hypermutation and class-switch recombination within
the germinal centers of lymphoid organs. These processes are regulated by follicular helper
T cells and follicular dendritic cells. The result is the selection of B cells with high affinity
for the specific antigen.
, 4. In Type I Hypersensitivity, the primary antibody isotype responsible for mast cell
degranulation is:
A. IgG
B. IgM
C. IgE
D. IgA
Answer: C
Rationale: Type I hypersensitivity involves the production of IgE antibodies in response to
common environmental allergens. These IgE molecules bind to high-affinity Fc receptors
on the surface of mast cells and basophils. Upon re-exposure, the allergen cross-links the
IgE, triggering the release of inflammatory mediators like histamine.
5. Which enzyme is responsible for the recombination of V, D, and J gene segments during
lymphocyte development?
A. AID
B. TdT
C. RAG-1/RAG-2
D. Caspase-3
Answer: C
