Immunology Chapters 5 & 6 Exam Prep 2026 – UCF
1. Which of the following molecules is NOT encoded within the MHC locus?
A. HLA-A
B. Beta-2 microglobulin
C. HLA-DR
D. TAP1
Answer: B
Rationale: Beta-2 microglobulin is essential for MHC Class I structure but is encoded on
chromosome 15, outside the MHC locus.
2. MHC Class I molecules typically bind peptides of what length?
A. 13-18 amino acids
B. 8-10 amino acids
C. Over 25 amino acids
D. 5-7 amino acids
Answer: B
Rationale: The closed ends of the MHC Class I binding cleft limit the peptide size to
typically 8-10 amino acids.
3. Which cell type would you expect NOT to express MHC Class I?
A. Liver cells
B. Red blood cells
C. Macrophages
D. Dendritic cells
Answer: B
,Rationale: MHC Class I is expressed on all nucleated cells; mature red blood cells lack a
nucleus and therefore do not express MHC I.
4. What is the primary function of the Invariant Chain (Ii)?
A. To transport peptides into the ER
B. To block the peptide-binding cleft of MHC Class II in the ER
C. To load peptides onto MHC Class I
D. To degrade viral proteins
Answer: B
Rationale: The Invariant Chain prevents endogenous peptides in the ER from binding to
MHC Class II molecules.
5. Which molecule is responsible for catalyzing the exchange of CLIP for an
antigenic peptide in MHC Class II?
A. Tapasin
B. HLA-DO
C. HLA-DM
D. Calnexin
Answer: C
Rationale: HLA-DM acts as a catalyst in the MIIC compartment to release CLIP so higher
affinity peptides can bind.
6. The polymorphism of MHC molecules is primarily concentrated in which
area?
A. The cytoplasmic tail
B. The peptide-binding cleft
C. The transmembrane region
D. The constant domains like Alpha-3
Answer: B
, Rationale: Polymorphism is highest in the cleft to allow the population to present a wide
variety of different pathogen-derived peptides.
7. Endogenous antigens are processed primarily by which structure?
A. The Lysosome
B. The Phagosome
C. The Proteasome
D. The Golgi Apparatus
Answer: C
Rationale: Cytosolic (endogenous) proteins are ubiquitinated and degraded by the
proteasome for presentation on MHC Class I.
8. Which of the following describes ‘Cross-Presentation’?
A. Presenting endogenous antigens on MHC II
B. Presenting self-antigens to B cells
C. Presenting exogenous antigens on MHC I
D. MHC molecules presenting lipids
Answer: C
Rationale: Cross-presentation allows dendritic cells to take up extracellular viral particles
and present them on MHC I to activate CD8+ T cells.
9. The term ‘haplotype’ in MHC genetics refers to:
A. The specific peptide bound to the MHC
B. A mutation in the MHC gene
C. The total number of MHC molecules on a cell surface
D. The set of MHC alleles on a single chromosome
Answer: D
Rationale: A haplotype is the linked set of MHC genes inherited together from one parent.
1. Which of the following molecules is NOT encoded within the MHC locus?
A. HLA-A
B. Beta-2 microglobulin
C. HLA-DR
D. TAP1
Answer: B
Rationale: Beta-2 microglobulin is essential for MHC Class I structure but is encoded on
chromosome 15, outside the MHC locus.
2. MHC Class I molecules typically bind peptides of what length?
A. 13-18 amino acids
B. 8-10 amino acids
C. Over 25 amino acids
D. 5-7 amino acids
Answer: B
Rationale: The closed ends of the MHC Class I binding cleft limit the peptide size to
typically 8-10 amino acids.
3. Which cell type would you expect NOT to express MHC Class I?
A. Liver cells
B. Red blood cells
C. Macrophages
D. Dendritic cells
Answer: B
,Rationale: MHC Class I is expressed on all nucleated cells; mature red blood cells lack a
nucleus and therefore do not express MHC I.
4. What is the primary function of the Invariant Chain (Ii)?
A. To transport peptides into the ER
B. To block the peptide-binding cleft of MHC Class II in the ER
C. To load peptides onto MHC Class I
D. To degrade viral proteins
Answer: B
Rationale: The Invariant Chain prevents endogenous peptides in the ER from binding to
MHC Class II molecules.
5. Which molecule is responsible for catalyzing the exchange of CLIP for an
antigenic peptide in MHC Class II?
A. Tapasin
B. HLA-DO
C. HLA-DM
D. Calnexin
Answer: C
Rationale: HLA-DM acts as a catalyst in the MIIC compartment to release CLIP so higher
affinity peptides can bind.
6. The polymorphism of MHC molecules is primarily concentrated in which
area?
A. The cytoplasmic tail
B. The peptide-binding cleft
C. The transmembrane region
D. The constant domains like Alpha-3
Answer: B
, Rationale: Polymorphism is highest in the cleft to allow the population to present a wide
variety of different pathogen-derived peptides.
7. Endogenous antigens are processed primarily by which structure?
A. The Lysosome
B. The Phagosome
C. The Proteasome
D. The Golgi Apparatus
Answer: C
Rationale: Cytosolic (endogenous) proteins are ubiquitinated and degraded by the
proteasome for presentation on MHC Class I.
8. Which of the following describes ‘Cross-Presentation’?
A. Presenting endogenous antigens on MHC II
B. Presenting self-antigens to B cells
C. Presenting exogenous antigens on MHC I
D. MHC molecules presenting lipids
Answer: C
Rationale: Cross-presentation allows dendritic cells to take up extracellular viral particles
and present them on MHC I to activate CD8+ T cells.
9. The term ‘haplotype’ in MHC genetics refers to:
A. The specific peptide bound to the MHC
B. A mutation in the MHC gene
C. The total number of MHC molecules on a cell surface
D. The set of MHC alleles on a single chromosome
Answer: D
Rationale: A haplotype is the linked set of MHC genes inherited together from one parent.
