PCB 3233 Immunology Exam 1 Review 2026 – UCF
1. Which of the following is a characteristic of the innate immune system?
A. It responds identically to repeated infections.
B. It requires a prior exposure to the pathogen.
C. It is highly specific for individual pathogens.
D. It involves the production of antibodies.
Answer: A
Rationale: The innate immune system is non-specific and lacks memory, meaning it
responds the same way every time it encounters a pathogen.
2. Where is the primary site of hematopoiesis in a healthy adult?
A. Liver
B. Bone Marrow
C. Spleen
D. Thymus
Answer: B
Rationale: In adults, the bone marrow is the primary site where all blood cells, including
immune cells, are produced.
3. Which leukocyte is usually the first to arrive at the site of an infection?
A. Monocyte
B. Neutrophil
C. B lymphocyte
D. Basophil
Answer: B
,Rationale: Neutrophils are the most abundant white blood cells and are typically the first
responders to inflammatory signals.
4. Which of the following are considered primary lymphoid organs?
A. Lymph nodes and Spleen
B. Thymus and Spleen
C. Peyer’s patches and Tonsils
D. Bone marrow and Thymus
Answer: D
Rationale: Primary lymphoid organs are where immune cells develop and mature (Bone
marrow and Thymus).
5. What is the main function of the Thymus?
A. Activation of B cells
B. Filtration of blood
C. Storage of platelets
D. T cell maturation and selection
Answer: D
Rationale: The thymus is the site where T cell precursors migrate to undergo maturation
and selection processes.
6. Which cell type expresses MHC Class II molecules?
A. Red blood cells
B. All nucleated cells
C. Professional Antigen Presenting Cells (APCs)
D. Neurons
Answer: C
Rationale: MHC Class II is primarily expressed by professional APCs like dendritic cells,
macrophages, and B cells.
, 7. MHC Class I molecules are found on which of the following?
A. Only on B cells and T cells
B. Only on Macrophages
C. All nucleated cells
D. Only on professional APCs
Answer: C
Rationale: MHC Class I is present on almost all nucleated cells in the body to present
endogenous antigens.
8. Which of the following is a key feature of adaptive immunity?
A. Immediate response
B. Immunological memory
C. Lack of specificity
D. Physical barriers like skin
Answer: B
Rationale: Memory is a hallmark of the adaptive immune system, allowing for a faster and
stronger response upon re-exposure.
9. Which antibody isotype is the first to be secreted during a primary immune
response?
A. IgG
B. IgA
C. IgM
D. IgE
Answer: C
Rationale: IgM is the first antibody class produced by B cells during the initial response to
an antigen.
1. Which of the following is a characteristic of the innate immune system?
A. It responds identically to repeated infections.
B. It requires a prior exposure to the pathogen.
C. It is highly specific for individual pathogens.
D. It involves the production of antibodies.
Answer: A
Rationale: The innate immune system is non-specific and lacks memory, meaning it
responds the same way every time it encounters a pathogen.
2. Where is the primary site of hematopoiesis in a healthy adult?
A. Liver
B. Bone Marrow
C. Spleen
D. Thymus
Answer: B
Rationale: In adults, the bone marrow is the primary site where all blood cells, including
immune cells, are produced.
3. Which leukocyte is usually the first to arrive at the site of an infection?
A. Monocyte
B. Neutrophil
C. B lymphocyte
D. Basophil
Answer: B
,Rationale: Neutrophils are the most abundant white blood cells and are typically the first
responders to inflammatory signals.
4. Which of the following are considered primary lymphoid organs?
A. Lymph nodes and Spleen
B. Thymus and Spleen
C. Peyer’s patches and Tonsils
D. Bone marrow and Thymus
Answer: D
Rationale: Primary lymphoid organs are where immune cells develop and mature (Bone
marrow and Thymus).
5. What is the main function of the Thymus?
A. Activation of B cells
B. Filtration of blood
C. Storage of platelets
D. T cell maturation and selection
Answer: D
Rationale: The thymus is the site where T cell precursors migrate to undergo maturation
and selection processes.
6. Which cell type expresses MHC Class II molecules?
A. Red blood cells
B. All nucleated cells
C. Professional Antigen Presenting Cells (APCs)
D. Neurons
Answer: C
Rationale: MHC Class II is primarily expressed by professional APCs like dendritic cells,
macrophages, and B cells.
, 7. MHC Class I molecules are found on which of the following?
A. Only on B cells and T cells
B. Only on Macrophages
C. All nucleated cells
D. Only on professional APCs
Answer: C
Rationale: MHC Class I is present on almost all nucleated cells in the body to present
endogenous antigens.
8. Which of the following is a key feature of adaptive immunity?
A. Immediate response
B. Immunological memory
C. Lack of specificity
D. Physical barriers like skin
Answer: B
Rationale: Memory is a hallmark of the adaptive immune system, allowing for a faster and
stronger response upon re-exposure.
9. Which antibody isotype is the first to be secreted during a primary immune
response?
A. IgG
B. IgA
C. IgM
D. IgE
Answer: C
Rationale: IgM is the first antibody class produced by B cells during the initial response to
an antigen.
