BIOD331 Module 3 Mechanisms of Self-defense:
immunity & dysfunctions
Comprehensive Final Test (Qns & Ans)
2025
Question 1 (Multiple Choice)
Question:
During T‑cell development in the thymus, which process is
primarily responsible for eliminating T cells that react strongly to
self‑antigens, thereby establishing central tolerance?
A) Positive selection
B) Negative selection
C) Clonal expansion
D) Anergy induction
Correct ANS:
©2025
,B) Negative selection
Rationale:
Negative selection in the thymus deletes T cells with high affinity
for self-antigens. This critical process prevents the emergence of
self-reactive T lymphocytes into the periphery and is fundamental
in establishing central tolerance.
---
Question 2 (Fill in the Blank)
Question:
Regulatory T cells (Tregs) maintain peripheral tolerance by
secreting anti-inflammatory cytokines such as ________, which
suppress the activation of autoreactive lymphocytes.
Correct ANS:
TGF‑β
Rationale:
TGF‑β, along with IL‑10, is a key anti-inflammatory cytokine
produced by Tregs that downregulates immune responses and
©2025
,helps maintain peripheral tolerance by inhibiting the activation
and proliferation of potentially harmful autoreactive T cells.
---
Question 3 (True/False)
Question:
True/False: A cytokine storm is an example of immune
dysfunction where an unregulated and excessive release of pro-
inflammatory cytokines results in systemic inflammation and
tissue damage.
Correct ANS:
True
Rationale:
A cytokine storm represents a hyperactive immune response with
massive secretion of cytokines (e.g., TNF‑α, IL‑1, IL‑6) that leads
to widespread inflammation, multi-organ dysfunction, and can be
life‑threatening if not controlled.
---
©2025
, Question 4 (Multiple Response)
Question:
Select all mechanisms by which pathogens can evade the host
immune response:
A) Antigenic variation
B) Secretion of immunosuppressive molecules
C) Formation of biofilms
D) Upregulation of MHC class I expression
E) Intracellular sequestration within host cells
Correct ANS:
A) Antigenic variation,
B) Secretion of immunosuppressive molecules,
C) Formation of biofilms,
E) Intracellular sequestration within host cells
Rationale:
Pathogens may alter their antigenic profile (A), secrete factors
that dampen immune responses (B), form biofilms that impede
drug penetration and immune recognition (C), or hide inside host
cells (E) to avoid immune detection. Upregulation of MHC class I
(D) would enhance, not hinder, immune recognition.
©2025
immunity & dysfunctions
Comprehensive Final Test (Qns & Ans)
2025
Question 1 (Multiple Choice)
Question:
During T‑cell development in the thymus, which process is
primarily responsible for eliminating T cells that react strongly to
self‑antigens, thereby establishing central tolerance?
A) Positive selection
B) Negative selection
C) Clonal expansion
D) Anergy induction
Correct ANS:
©2025
,B) Negative selection
Rationale:
Negative selection in the thymus deletes T cells with high affinity
for self-antigens. This critical process prevents the emergence of
self-reactive T lymphocytes into the periphery and is fundamental
in establishing central tolerance.
---
Question 2 (Fill in the Blank)
Question:
Regulatory T cells (Tregs) maintain peripheral tolerance by
secreting anti-inflammatory cytokines such as ________, which
suppress the activation of autoreactive lymphocytes.
Correct ANS:
TGF‑β
Rationale:
TGF‑β, along with IL‑10, is a key anti-inflammatory cytokine
produced by Tregs that downregulates immune responses and
©2025
,helps maintain peripheral tolerance by inhibiting the activation
and proliferation of potentially harmful autoreactive T cells.
---
Question 3 (True/False)
Question:
True/False: A cytokine storm is an example of immune
dysfunction where an unregulated and excessive release of pro-
inflammatory cytokines results in systemic inflammation and
tissue damage.
Correct ANS:
True
Rationale:
A cytokine storm represents a hyperactive immune response with
massive secretion of cytokines (e.g., TNF‑α, IL‑1, IL‑6) that leads
to widespread inflammation, multi-organ dysfunction, and can be
life‑threatening if not controlled.
---
©2025
, Question 4 (Multiple Response)
Question:
Select all mechanisms by which pathogens can evade the host
immune response:
A) Antigenic variation
B) Secretion of immunosuppressive molecules
C) Formation of biofilms
D) Upregulation of MHC class I expression
E) Intracellular sequestration within host cells
Correct ANS:
A) Antigenic variation,
B) Secretion of immunosuppressive molecules,
C) Formation of biofilms,
E) Intracellular sequestration within host cells
Rationale:
Pathogens may alter their antigenic profile (A), secrete factors
that dampen immune responses (B), form biofilms that impede
drug penetration and immune recognition (C), or hide inside host
cells (E) to avoid immune detection. Upregulation of MHC class I
(D) would enhance, not hinder, immune recognition.
©2025
