NR 507 Midterm Examination (Weeks 1–4)
Questions and Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
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1. Which immunoglobulin is the first antibody produced during a
primary immune response?
A. IgA
B. IgE
C. IgM
D. IgG
Rationale: IgM is the first immunoglobulin synthesized during a
primary immune response. It is highly effective at activating the
complement system because of its pentameric structure. As the
immune response matures, B cells undergo class switching and
produce IgG, IgA, or IgE depending on the antigen and cytokine
environment.
, 2. Which type of hypersensitivity reaction is responsible for
anaphylaxis?
A. Type II
B. Type III
C. Type IV
D. Type I
Rationale: Type I hypersensitivity is an immediate allergic reaction
mediated by IgE antibodies bound to mast cells and basophils. Upon
re-exposure to an allergen, histamine and other inflammatory
mediators are rapidly released, producing symptoms ranging from
urticaria to life-threatening anaphylaxis.
3. Which immune cell is primarily responsible for presenting antigens
to naïve T lymphocytes?
A. Neutrophil
B. Eosinophil
C. Dendritic cell
D. Platelet
Rationale: Dendritic cells are the most effective antigen-presenting
cells. They capture pathogens, process antigens, and present them to
,naïve T cells through major histocompatibility complex (MHC)
molecules, initiating the adaptive immune response.
4. Which cytokine is primarily responsible for stimulating fever
during infection?
A. Interleukin-10
B. Interleukin-4
C. Interleukin-1
D. Transforming growth factor-beta
Rationale: Interleukin-1 (IL-1) is an important pro-inflammatory
cytokine that acts on the hypothalamus to increase body temperature.
It also stimulates leukocyte activation and promotes the acute
inflammatory response.
5. A deficiency of which complement component is most strongly
associated with recurrent Neisseria infections?
A. C1
B. C3
C. C4
D. C5-C9
, Rationale: Deficiencies in C5 through C9, which form the membrane
attack complex (MAC), significantly increase susceptibility to Neisseria
infections because these bacteria are effectively killed through
complement-mediated lysis.
6. Which leukocyte is most commonly elevated in parasitic
infections?
A. Basophil
B. Monocyte
C. Neutrophil
D. Eosinophil
Rationale: Eosinophils play a major role in defending against parasitic
infections and are also active in allergic disorders. They release toxic
granules that damage parasites while contributing to inflammation.
7. Which process generates antibody diversity before exposure to
antigens?
A. Somatic mutation only
B. Gene duplication
Questions and Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
1. Which immunoglobulin is the first antibody produced during a
primary immune response?
A. IgA
B. IgE
C. IgM
D. IgG
Rationale: IgM is the first immunoglobulin synthesized during a
primary immune response. It is highly effective at activating the
complement system because of its pentameric structure. As the
immune response matures, B cells undergo class switching and
produce IgG, IgA, or IgE depending on the antigen and cytokine
environment.
, 2. Which type of hypersensitivity reaction is responsible for
anaphylaxis?
A. Type II
B. Type III
C. Type IV
D. Type I
Rationale: Type I hypersensitivity is an immediate allergic reaction
mediated by IgE antibodies bound to mast cells and basophils. Upon
re-exposure to an allergen, histamine and other inflammatory
mediators are rapidly released, producing symptoms ranging from
urticaria to life-threatening anaphylaxis.
3. Which immune cell is primarily responsible for presenting antigens
to naïve T lymphocytes?
A. Neutrophil
B. Eosinophil
C. Dendritic cell
D. Platelet
Rationale: Dendritic cells are the most effective antigen-presenting
cells. They capture pathogens, process antigens, and present them to
,naïve T cells through major histocompatibility complex (MHC)
molecules, initiating the adaptive immune response.
4. Which cytokine is primarily responsible for stimulating fever
during infection?
A. Interleukin-10
B. Interleukin-4
C. Interleukin-1
D. Transforming growth factor-beta
Rationale: Interleukin-1 (IL-1) is an important pro-inflammatory
cytokine that acts on the hypothalamus to increase body temperature.
It also stimulates leukocyte activation and promotes the acute
inflammatory response.
5. A deficiency of which complement component is most strongly
associated with recurrent Neisseria infections?
A. C1
B. C3
C. C4
D. C5-C9
, Rationale: Deficiencies in C5 through C9, which form the membrane
attack complex (MAC), significantly increase susceptibility to Neisseria
infections because these bacteria are effectively killed through
complement-mediated lysis.
6. Which leukocyte is most commonly elevated in parasitic
infections?
A. Basophil
B. Monocyte
C. Neutrophil
D. Eosinophil
Rationale: Eosinophils play a major role in defending against parasitic
infections and are also active in allergic disorders. They release toxic
granules that damage parasites while contributing to inflammation.
7. Which process generates antibody diversity before exposure to
antigens?
A. Somatic mutation only
B. Gene duplication
