PCB 3233 Final Exam V1 | PCB 3233
Immunology | Actual Q&A with Rationale
(PCB3233 Final Exam | University of
Central Florida
1. Which of the following describes the mechanism by which the membrane attack complex
(MAC) induces cell lysis?
A. Activation of the caspase cascade within the target cell
B. Formation of hydrophilic pores in the lipid bilayer of the pathogen membrane
C. Degradation of the bacterial cell wall via lysozyme activity
D. Opsonization of the pathogen for phagocytic recognition
Answer: B
Rationale: The membrane attack complex is the end product of the complement cascade. It
is composed of C5b, C6, C7, C8, and multiple C9 molecules. These components assemble to
form a pore that disrupts the osmotic integrity of the target cell, leading to lysis.
2. A patient presents with a defect in the RAG-1 and RAG-2 genes. Which of the following
immunologic phenotypes would you expect to observe?
A. A total lack of innate immune cells like neutrophils
B. A complete absence of mature B and T lymphocytes
C. Hyper-production of IgM with a lack of IgG and IgE
,D. Inability of MHC molecules to present antigens
Answer: B
Rationale: RAG-1 and RAG-2 are essential enzymes for V(D)J recombination in the
development of B and T cell receptors. Without these enzymes, lymphocytes cannot
undergo the gene rearrangement necessary for functional receptor expression. This
condition results in severe combined immunodeficiency (SCID) due to the failure of
adaptive immunity.
3. Which Toll-like receptor (TLR) is specifically responsible for recognizing lipopolysaccharide
(LPS) on Gram-negative bacteria?
A. TLR3
B. TLR9
C. TLR5
D. TLR4
Answer: D
Rationale: TLR4 is a member of the pattern recognition receptor family that identifies the
lipid A portion of LPS. It works in conjunction with MD-2 and CD14 to trigger a signaling
cascade through MyD88. This recognition is a critical component of the innate immune
response to Gram-negative infections.
, 4. During an inflammatory response, which cytokine acts on the hypothalamus to induce
fever?
A. IL-10
B. TGF-beta
C. IFN-gamma
D. IL-1
Answer: D
Rationale: Interleukin-1 (IL-1) is a pro-inflammatory cytokine produced primarily by
macrophages. It functions as an endogenous pyrogen by stimulating the production of
prostaglandins in the hypothalamus. This shift in the thermoregulatory set-point results in
a systemic fever response.
5. Which of the following MHC-peptide interactions is correct regarding T cell activation?
A. CD4 T cells recognize peptides presented on MHC Class I
B. Natural Killer cells recognize peptides presented on MHC Class II
C. CD8 T cells recognize peptides presented on MHC Class II
D. CD8 T cells recognize peptides presented on MHC Class I
Answer: D
Rationale: MHC Class I molecules are expressed on all nucleated cells and present
endogenous antigens to CD8+ cytotoxic T cells. MHC Class II molecules are expressed on
Immunology | Actual Q&A with Rationale
(PCB3233 Final Exam | University of
Central Florida
1. Which of the following describes the mechanism by which the membrane attack complex
(MAC) induces cell lysis?
A. Activation of the caspase cascade within the target cell
B. Formation of hydrophilic pores in the lipid bilayer of the pathogen membrane
C. Degradation of the bacterial cell wall via lysozyme activity
D. Opsonization of the pathogen for phagocytic recognition
Answer: B
Rationale: The membrane attack complex is the end product of the complement cascade. It
is composed of C5b, C6, C7, C8, and multiple C9 molecules. These components assemble to
form a pore that disrupts the osmotic integrity of the target cell, leading to lysis.
2. A patient presents with a defect in the RAG-1 and RAG-2 genes. Which of the following
immunologic phenotypes would you expect to observe?
A. A total lack of innate immune cells like neutrophils
B. A complete absence of mature B and T lymphocytes
C. Hyper-production of IgM with a lack of IgG and IgE
,D. Inability of MHC molecules to present antigens
Answer: B
Rationale: RAG-1 and RAG-2 are essential enzymes for V(D)J recombination in the
development of B and T cell receptors. Without these enzymes, lymphocytes cannot
undergo the gene rearrangement necessary for functional receptor expression. This
condition results in severe combined immunodeficiency (SCID) due to the failure of
adaptive immunity.
3. Which Toll-like receptor (TLR) is specifically responsible for recognizing lipopolysaccharide
(LPS) on Gram-negative bacteria?
A. TLR3
B. TLR9
C. TLR5
D. TLR4
Answer: D
Rationale: TLR4 is a member of the pattern recognition receptor family that identifies the
lipid A portion of LPS. It works in conjunction with MD-2 and CD14 to trigger a signaling
cascade through MyD88. This recognition is a critical component of the innate immune
response to Gram-negative infections.
, 4. During an inflammatory response, which cytokine acts on the hypothalamus to induce
fever?
A. IL-10
B. TGF-beta
C. IFN-gamma
D. IL-1
Answer: D
Rationale: Interleukin-1 (IL-1) is a pro-inflammatory cytokine produced primarily by
macrophages. It functions as an endogenous pyrogen by stimulating the production of
prostaglandins in the hypothalamus. This shift in the thermoregulatory set-point results in
a systemic fever response.
5. Which of the following MHC-peptide interactions is correct regarding T cell activation?
A. CD4 T cells recognize peptides presented on MHC Class I
B. Natural Killer cells recognize peptides presented on MHC Class II
C. CD8 T cells recognize peptides presented on MHC Class II
D. CD8 T cells recognize peptides presented on MHC Class I
Answer: D
Rationale: MHC Class I molecules are expressed on all nucleated cells and present
endogenous antigens to CD8+ cytotoxic T cells. MHC Class II molecules are expressed on
