1.Which cell type is NOT part of the innate immune
system?
A. Neutrophil
B. Macrophage
C. Dendritic cell
D. Plasma cell
o Answer: D. Plasma cell
o Rationale: Plasma cells are differentiated B cells
of the adaptive immune system that secrete
antibodies.
2. Toll‐like receptors (TLRs) recognize:
A. Self antigens
B. Pathogen‐associated molecular patterns (PAMPs)
C. Cytokines
D. Major histocompatibility complexes
o Answer: B. PAMPs
o Rationale: TLRs on innate immune cells bind
conserved microbial structures (PAMPs),
initiating immune activation (Sanfoundry).
3. Which innate cell type specializes in killing virally
infected cells without prior sensitization?
A. Natural killer (NK) cell
B. Eosinophil
C. Basophil
D. Mast cell
o Answer: A. NK cell
, o Rationale: NK cells induce apoptosis in infected
cells via perforin/granzyme pathways
(Sanfoundry).
4. The inflammatory cytokine primarily responsible
for fever induction is:
A. IL‐2
B. IL‐6
C. TNF‐α
D. IL‐1β
o Answer: D. IL‐1β
o Rationale: IL‐1β acts on the hypothalamus to
raise body temperature during infection.
5. Which complement pathway is initiated by
antigen‐antibody complexes?
A. Classical
B. Lectin
C. Alternative
D. Mannose‐binding
o Answer: A. Classical
o Rationale: The classical pathway is activated
when C1q binds to immune complexes.
6. Phagocytes recognize pathogens via:
A. Complement receptors
B. Pattern recognition receptors (PRRs)
C. Immunoglobulin receptors only
D. Both A and B
, o Answer: D. Both A and B
o Rationale: Phagocytes use PRRs (e.g., TLRs)
and complement receptors to bind and ingest
microbes (Sanfoundry).
7. Which molecule directly opsonizes bacteria?
A. IL‐10
B. C3b
C. IgD
D. MHC II
o Answer: B. C3b
o Rationale: C3b coats pathogens, enhancing
phagocytosis via complement receptors.
8. Mast cells release histamine primarily during:
A. Viral infections
B. Allergic reactions
C. Autoimmune responses
D. Tumor surveillance
o Answer: B. Allergic reactions
o Rationale: Mast cell degranulation releases
histamine in Type I hypersensitivity.
9. In innate immunity, “first responders” to bacterial
infection are:
A. Neutrophils
B. NK cells
C. T lymphocytes
D. B lymphocytes
system?
A. Neutrophil
B. Macrophage
C. Dendritic cell
D. Plasma cell
o Answer: D. Plasma cell
o Rationale: Plasma cells are differentiated B cells
of the adaptive immune system that secrete
antibodies.
2. Toll‐like receptors (TLRs) recognize:
A. Self antigens
B. Pathogen‐associated molecular patterns (PAMPs)
C. Cytokines
D. Major histocompatibility complexes
o Answer: B. PAMPs
o Rationale: TLRs on innate immune cells bind
conserved microbial structures (PAMPs),
initiating immune activation (Sanfoundry).
3. Which innate cell type specializes in killing virally
infected cells without prior sensitization?
A. Natural killer (NK) cell
B. Eosinophil
C. Basophil
D. Mast cell
o Answer: A. NK cell
, o Rationale: NK cells induce apoptosis in infected
cells via perforin/granzyme pathways
(Sanfoundry).
4. The inflammatory cytokine primarily responsible
for fever induction is:
A. IL‐2
B. IL‐6
C. TNF‐α
D. IL‐1β
o Answer: D. IL‐1β
o Rationale: IL‐1β acts on the hypothalamus to
raise body temperature during infection.
5. Which complement pathway is initiated by
antigen‐antibody complexes?
A. Classical
B. Lectin
C. Alternative
D. Mannose‐binding
o Answer: A. Classical
o Rationale: The classical pathway is activated
when C1q binds to immune complexes.
6. Phagocytes recognize pathogens via:
A. Complement receptors
B. Pattern recognition receptors (PRRs)
C. Immunoglobulin receptors only
D. Both A and B
, o Answer: D. Both A and B
o Rationale: Phagocytes use PRRs (e.g., TLRs)
and complement receptors to bind and ingest
microbes (Sanfoundry).
7. Which molecule directly opsonizes bacteria?
A. IL‐10
B. C3b
C. IgD
D. MHC II
o Answer: B. C3b
o Rationale: C3b coats pathogens, enhancing
phagocytosis via complement receptors.
8. Mast cells release histamine primarily during:
A. Viral infections
B. Allergic reactions
C. Autoimmune responses
D. Tumor surveillance
o Answer: B. Allergic reactions
o Rationale: Mast cell degranulation releases
histamine in Type I hypersensitivity.
9. In innate immunity, “first responders” to bacterial
infection are:
A. Neutrophils
B. NK cells
C. T lymphocytes
D. B lymphocytes
